Add documentation backed by mkdocs (#883)

Affects /docs - (Refined Documentation for deployment and added Some
Supporting documentation)
Added a github action for deployment

Fixes #835  

Added Support for mkdocs
Example -  https://dinesht04.github.io/go-sdk/

Requires Configuration of Github pages as follows:-

1. Enable Github Pages
2. Select gh-pages branch for deployment

<img width="1237" height="817" alt="gh-pages"
src="https://github.com/user-attachments/assets/01f0b012-d5f3-4011-9af9-7269e657ae6a"
/>

## Sources
# For mkdocs.yaml
1.
https://github.com/modelcontextprotocol/python-sdk/blob/main/mkdocs.yml
2. https://github.com/modelcontextprotocol/java-sdk/blob/main/mkdocs.yml
  3. MKDocs official documentation
# For Github Action
1.
https://github.com/modelcontextprotocol/python-sdk/blob/main/.github/workflows/publish-docs-manually.yml
2.
https://github.com/modelcontextprotocol/java-sdk/blob/main/.github/workflows/docs.yml
3.
https://github.com/james-willett/material-mkdocs-youtube-2024/blob/main/.github/workflows/ci.yml
- From Youtube Tutorial

internal/docs/README.src.md

@@ -1,4 +1,21 @@
-# Features
+# Overview
+
+The SDK consists of several importable packages:
+
+- The
+  [`github.com/modelcontextprotocol/go-sdk/mcp`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/mcp)
+  package defines the primary APIs for constructing and using MCP clients and
+  servers.
+- The
+  [`github.com/modelcontextprotocol/go-sdk/jsonrpc`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/jsonrpc) package is for users implementing
+  their own transports.
+- The
+  [`github.com/modelcontextprotocol/go-sdk/auth`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/auth)
+  package provides some primitives for supporting OAuth.
+- The
+  [`github.com/modelcontextprotocol/go-sdk/oauthex`](https://pkg.go.dev/github.com/modelcontextprotocol/go-sdk/oauthex)
+  package provides extensions to the OAuth protocol, such as ProtectedResourceMetadata.
+
 
 These docs mirror the [official MCP spec](https://modelcontextprotocol.io/specification/2025-06-18).
 Use the index below to learn how the SDK implements a particular aspect of the