[Fundamentals] Concepts cleanup (#20222)

* Small concepts updates and added redirects

* Moved Free plan page

* Updated page order

* Updated links and partials

Author: dcpena

public/_redirects

@@ -557,7 +557,7 @@
 /fundamentals/get-started/setup/ /fundamentals/setup/ 301
 /fundamentals/get-started/setup/minimize-downtime/ /fundamentals/performance/minimize-downtime/ 301
 /fundamentals/basic-tasks/maintenance-mode/ /fundamentals/performance/minimize-downtime/ 301
-/fundamentals/get-started/concepts/what-is-cloudflare/ /fundamentals/concepts/what-is-cloudflare/ 301
+/fundamentals/get-started/concepts/what-is-cloudflare/ https://www.cloudflare.com/learning/what-is-cloudflare/ 301
 /fundamentals/get-started/concepts/cloudflare-challenges/ /waf/reference/cloudflare-challenges/ 301
 /fundamentals/get-started/concepts/accounts-and-zones/ /fundamentals/setup/accounts-and-zones/ 301
 /fundamentals/get-started/concepts/cloudflare-ip-addresses/ /fundamentals/concepts/cloudflare-ip-addresses/ 301
@@ -638,6 +638,9 @@
 /fundamentals/security/trace-request/how-to/ /fundamentals/trace-request/how-to/ 301
 /fundamentals/security/trace-request/limitations/ /fundamentals/trace-request/limitations/ 301
 /fundamentals/security/trace-request/changelog/ /fundamentals/trace-request/changelog/ 301
+/fundamentals/concepts/what-is-cloudflare/ https://www.cloudflare.com/learning/what-is-cloudflare/ 301
+/fundamentals/concepts/the-internet/ https://www.cloudflare.com/learning/network-layer/how-does-the-internet-work/ 301
+/fundamentals/concepts/free-plan/ /fundamentals/subscriptions-and-billing/free-plan/ 301
 
 # gateway
 /gateway/about/ /cloudflare-one/policies/gateway/ 301

src/content/docs/fundamentals/concepts/the-internet.mdx

@@ -2,7 +2,7 @@
 pcx_content_type: concept
 title: Our Free plan
 sidebar:
-  order: 4
+  order: 1
 head:
   - tag: title
     content: Why Cloudflare offers a free plan

src/content/docs/fundamentals/concepts/what-is-cloudflare.mdx

@@ -8,7 +8,7 @@ sidebar:
 
 import { Render } from "~/components"
 
-<Render file="how-cloudflare-works" product="fundamentals" />
+Fundamentally, Cloudflare is a [large network of servers](https://www.cloudflare.com/learning/what-is-cloudflare/) that can improve the security, performance, and reliability of anything connected to the Internet.
 
 ## Life of a request
 

src/content/docs/fundamentals/concepts/reference-architecture.mdx renamed to src/content/docs/fundamentals/reference-architecture.mdx

@@ -7,6 +7,6 @@ import { Stream } from "~/components"
 
 <Stream videoId="bdf5733bed92deded731efee29b2346f" videoTitle="What is Cloudflare?" thumbnailTimeOrURL="38s" />
 
-Cloudflare is one of the world’s largest [connectivity cloud networks](https://blog.cloudflare.com/welcome-to-connectivity-cloud). Today, anyone with an Internet presence can have faster and more secure websites and applications thanks to Cloudflare. This includes bloggers, businesses, and even non-profits.
+Cloudflare is one of the world's largest [connectivity cloud networks](https://blog.cloudflare.com/welcome-to-connectivity-cloud). Today, anyone with an Internet presence can have faster and more secure websites and applications thanks to Cloudflare. This includes bloggers, businesses, and even non-profits.
 
 Millions of Internet properties are on Cloudflare, and our network is growing by tens of thousands each day. Cloudflare powers Internet requests for millions of websites and serves 55 million HTTP requests per second on average.

src/content/docs/fundamentals/concepts/free-plan.mdx renamed to src/content/docs/fundamentals/subscriptions-and-billing/free-plan.mdx

@@ -3,4 +3,4 @@
 
 ---
 
-* What is Cloudflare? | [Website](https://www.cloudflare.com/what-is-cloudflare/) (5 minute read) or [video](/fundamentals/concepts/what-is-cloudflare/) (2 minutes)
+* What is Cloudflare? | [Website](https://www.cloudflare.com/what-is-cloudflare/) (5 minute read) or [video](https://youtu.be/XHvmX3FhTwU?feature=shared) (2 minutes)