chore: replace huge mermaid with tam diagram (open-component-model#1826)

<!-- markdownlint-disable MD041 -->
#### What this PR does / why we need it
This diagram provides a concise overview of the architecture of the ocm
k8s toolkit and the interaction between the different services involved.

#### Which issue(s) this PR fixes
<!--
Usage: `Fixes #<issue number>`, or `Fixes (paste link of issue)`.
-->

---------

Signed-off-by: Fabian Burth <fabian.burth@sap.com>

Author: fabianburth

kubernetes/controller/README.md

@@ -25,117 +25,13 @@ You should be familiar with the following concepts:
 > The following section provides a high-level overview of the OCM K8s Toolkit and its components regarding the
 > deployment of an OCM resource in a very basic scenario.
 
-The primary purpose of OCM K8s Toolkit is simple: Deploy an OCM resource from an OCM component version into a Kubernetes
-cluster.
-
-The implementation, however, is a bit more complex as deployments must be secure and configurable. Additionally, an
-OCM Resource can, in theory, contain any form of deployable resource, for instance a Helm chart, a Kustomization, or
-plain Kubernetes manifests. Each of these resources has its own way of being deployed or
-configured. So, instead of creating a generic deployer that offers all these functionalities, we decided to use existing
-tools that are already available in the Kubernetes ecosystem.
-
-The following diagram describes a basic scenario in which an OCM resource containing a Helm chart is deployed into a
-Kubernetes cluster using the OCM K8s Toolkit as well as kro and FluxCD.
-kro is used to orchestrate the deployment and to transport information about the location of the OCM resource to FluxCD.
-FluxCD takes the location of the OCM resource, downloads the chart, configures it if necessary,
-and deploys it into the Kubernetes cluster.
-
-```mermaid
-flowchart TB
-    classDef cluster fill:white,color:black,stroke:black;
-    classDef reconciledBy fill:#dedede,stroke:black,stroke-dasharray: 5,color:black;
-    classDef k8sObject fill:#b3b3b3,color:black,stroke:black;
-    classDef information fill:#b3b3b3,color:black,stroke:black,stroke-dasharray: 2;
-    classDef ocm fill:white,stroke:black,color:black;
-    classDef legendStyle fill:white,stroke:black,color:black,stroke-dasharray: 2;
-    classDef legendStartEnd height:0px;
-    classDef legendItems fill:#b3b3b3,stroke:none,color:black;
-
-    subgraph legend[Legend]
-        start1[ ] ---references[referenced by] --> end1[ ]
-        start2[ ] -.-creates -.-> end2[ ]
-        start3[ ] ---instanceOf[instance of] --> end3[ ]
-        start4[ ] ~~~reconciledBy[reconciled by] ~~~ end4[ ]
-        start5[ ] ~~~k8sObject[k8s object] ~~~ end5[ ]
-        start6[ ] ~~~templateOf[template of] ~~~ end6[ ]
-    end
-
-    subgraph background[ ]
-        direction TB
-
-        subgraph ocmRepo[OCM Repository]
-           subgraph ocmCV[OCM Component Version]
-               subgraph ocmResource[OCM Resource: HelmChart]
-               end
-           end
-        end
-
-        subgraph k8sCluster[Kubernetes Cluster]
-            subgraph kroRGD[kro]
-                subgraph rgd[RGD: Simple]
-                    direction LR
-                    rgdRepository[Repository]
-                    rgdComponent[Component]
-                    rgdResourceHelm[Resource: HelmChart]
-                    rgdSource[FluxCD: OCI Repository]
-                    rgdHelmRelease[FluxCD: HelmRelease]
-                end
-            end
-            subgraph kroInstance[kro]
-                subgraph instanceSimple[Instance: Simple]
-                    subgraph ocmK8sToolkit[OCM K8s Toolkit]
-                        k8sRepo[Repository] --> k8sComponent[Component] --> k8sResource[Resource: HelmChart]
-                    end
-                    subgraph fluxCD[FluxCD]
-                        source[OCI Repository] --> helmRelease[HelmRelease]
-                    end
-                    k8sResource --> source
-                end
-            end
-            kroRGD & instanceSimple --> crdSimple[CRD: Simple]
-            helmRelease --> deployment[Deployment: Helm chart]
-        end
-
-        ocmRepo --> k8sRepo
-    end
-
-    linkStyle default fill:none,stroke:black;
-    linkStyle 2,3,16,18 stroke:black,stroke-dasharray: 10;
-    linkStyle 4,5,17 stroke:black,stroke-dasharray: 4;
-
-    class start1,end1,start2,end2,start3,end3,start4,end4,start5,end5,start6,end6 legendStartEnd;
-    class references,creates,instanceOf legendItems;
-    class templateOf,rgdRepository,rgdComponent,rgdResourceHelm,rgdSource,rgdHelmRelease information;
-    class reconciledBy,ocmK8sToolkit,fluxCD,kroRGD,kroInstance reconciledBy;
-    class k8sObject,rgd,k8sRepo,k8sComponent,k8sResource,source,helmRelease,deployment,crdSimple,instanceSimple k8sObject;
-    class ocmRepo,ocmCV,ocmResource ocm;
-    class k8sCluster cluster;
-    class legend legendStyle;
-```
-
-The above diagram shows an OCM resource of type `helmChart`. This resource is part of an OCM component version,
-which is located in an OCM repository.
-
-In the `Kubernetes Cluster` we can see several Kubernetes (custom) resources. The `ResourceGraphDefintion`
-(`RGD: Simple`) contains the template of all the resources for deploying the Helm chart into the Kubernetes cluster.
-kro creates a Custom Resource Definition (CRD) `Simple` based on that `ResourceGraphDefinition`. By creating an instance
-of this CRD (`Instance: Simple`), the resources are created and reconciled by the respective controllers:
-
-- `Repository`: Points to the OCM repository and checks if it is reachable by pinging it.
-- `Component`: Refers to the `Repository` and downloads and verifies the OCM component version descriptor.
-- `Resource`: Points to the `Component`, downloads the OCM component version descriptor from which it gets the location
-of the OCM resource. It then downloads the resource to verify its signature (optional) and publishes the location of the
-resource in its status.
+The primary purpose of OCM K8s Toolkit is simple: Deploy an OCM resource 
+from an OCM component version into a Kubernetes cluster.
 
-> [!IMPORTANT]
-> With FluxCD, this only works if the OCM resource has an access for which FluxCD has a corresponding Source type (e.g.
-> an OCI or a GitHub repository)
-
-As a result, FluxCD can now consume the information of the `Resource` and deploy the Helm chart:
+The diagram below provides an overview of the architecture of the OCM 
+K8s Toolkit.
 
-- `OCIRepository`: Watches and downloads the resource from the location provided by the `Resource` status.
-- `HelmRelease`: Refers to the `OCIRepository`, lets you configure the Helm chart, and creates the deployment into the
-Kubernetes cluster.
+![Architecture of OCM K8s Toolkit](./docs/assets/controller-tam.svg)
 
 ## Installation