[Feature] - Merge reference.json and extension_map.json, plus documentation generator fixes

[montezdesousa]

1. Why?

   • python website/generate_platform_v4_markdown.py only checks if the extensions are installed, but to generate the full documentation we need them to be installed and built into reference.json
   • This caused the documentation to be deployed with the default provider extensions only
   • The information about python files built with openbb.build() is split between reference.json and extension_map.json
   • There is no information about which openbb-core version was used to generate the static assets
   • obb.coverage.reference can equivalent to openapi.json so it makes more sense to access it from the root

2. What?

   • Merge extension_map.json into referece.json and follow a OpenAPI like format, see screenshot below
   • Adjust the generate_platform_v4_markdown.py script to this change
   • With this information inside the reference we now check if all openbb dependencies are installed and built. It also performs version check
   • Expose reference with obb.reference
   • Expose core version in SystemSettings

3. Impact

   • Website documentation will fail if some extension is not installed or built into reference.json (it also fails if version is unexpected)
   • @hjoaquim how does this look? Can you adjust CLI to obb.reference and get the commands from reference.json paths property?

4. Testing Done:

   • Tested building with and without the optional extensions
   • Tested auto build with installed extensions and importing the package
   • Tested tampering reference.json extension versions to be incompatible with toml spec
   • Tested running python website/generate_platform_v4_markdown.py in several scenarios with and without built extensions
   • Ran integration tests for core and equity