[Doc] Add missing API docs

Is your suggestion related to a missing or misleading document? Please describe. The following set of APIs is not documented. Check the validity and add the APIs to public docs (some might not be promoted)

[x] - Advisory Management API /api/server/v1/admin-advisory-management/banner
[x] - Association Management API (Admin and user both)
[x] - Authenticators Management API | /api/server/v1/authenticators
[x] - Extension Management API | /api/server/v1/extensions ~- [ ] - Identity Verifier Management API | /api/server/v1/idv-providers~-> Not documenting because feature is not fully completed ~- [ ] - Secret Type Management API | /api/server/v1/secret-type~ -> Not documenting due to https://github.com/wso2/product-is/issues/19515 ~- [ ] - Secret Management API | /api/server/v1/secrets~ -> Not documenting due to https://github.com/wso2/product-is/issues/19515 ~- [ ] - IDV Claim Management API | /api/users/v1/(.*)/idv~ -> Not documenting because feature is not fully completed
[x] - User Management API | /api/identity/user/v1.0
[x] - Brading Preferences API | /api/server/v1/branding-preference
[x] - Account Recovery API | /api/users/v2/recovery
[x] - Expired password identification API | /api/server/v1/expired-password-identification
[x] - Functionality Management API (Admin and user API) | /api/users/v1/(.)/user-functionality/(.)
[x] - Organization Discovery API | /api/server/v1/the organizations/discovery
[x] - Offline user invite API
[x] - Idle user account identification API
[x] - Input Validation Rest API

Add missing organization-level APIs

[x] Branding API
[x] Idle Account Identification Management API | /o/api/idle-account-identification/v1/inactive-users
[x] Claim Management API | /o/api/server/v1/claim-dialects
[x] Identity Recovery | /o/api/identity/recovery
[x] Authenticators Management API | /o/api/server/v1/authenticators
[x] Expired Password Identification API | /o/api/server/v1/expired-password-identification
[x] Organization Discovery API | /o/api/server/v1/organizations/discovery
[x] SCIM2 Bulk API | /o/scim2/Bulk
[x] Offline user invite API

wso2 / product-is

[Doc] Add missing API docs #18427