Simplify docs and remove Docker local setup (#4783)

Having 2 different dev setups caused confusion, let's remove the Docker
local setup and recommend people install yarn locally.

Also simplified some docs by merging pages together, the recommend
self-hosting option is now the docker-compose / to adapt the
docker-compose.

packages/twenty-docker/twenty-front/serve.json

@@ -0,0 +1,6 @@
+{
+  "rewrites": [
+    { "source": "!static/**", "destination": "/index.html" }
+  ],
+  "directoryListing": false
+}