Make flux v1 an optional tooling

[NikitaGandhi]

Our CI/CD tooling - Flux Legacy, or Flux v1 is deprecated. Currently Flux V1 comes as a default installation as part of the odc_k8s module. Let's make it an optional tooling to allow platform end user decide what GitOps tool to install to manage their deployments. Some considerations - argoCD vs Flux v2.

Notes from @woodcockr :
Our reviews of both flux v2 and ArgoCD show little difference for our current use case except Argo CD has a pretty GUI, which also means it has a larger security footprint which it failed at recently (something to keep in mind). It plays nice with Argo Events and Workflows which combined with some other tooling means you can run your entire CI/CD pipeline on you own cluster without much suffering. Also combines with Argo Rollout (for canary deployments) and on paper at least appears to have better multi-cluster deployment support (which in our case might be handy).
My colleague Geoff has done a flux v2 from scratch install before and it was fine so we may just go the simplest path (which that would be) unless I get heartily sick once more of our enterprises chosen CI/CD environment and do everything.

[NikitaGandhi]

As discussed with the group, the plan is:

• update odc_k8s module and make Flux V1 optional with deprecated warning
• leave option for end user to choose their own CI/CD tooling - Flux v2, argo CD, etc