docs: Endpoints

[maduvena]

• Session Revocation endpoint documentation #3495
• document Authorization endpoint #3454
• Backchannel Authentication endpoint documentation
• clientinfo endpoint documentation #3518
• device authorization endpoint #3036
• end session endpoint documentation #3511
• docs: introspection #3037
• jwks_uri endpoint documentation #3535
• par endpoint documentation #3607
• token endpoint documentation #3591
• userinfo #3445
• registration endpoint documentation
• token revocation endpoint documentation #3492
• ssa endpoint documentation #3561

[ossdhaval]

Closing this issue as we are now tracking documentation completion by raising individual GH issues for each document.