Add a guide page on credential types (#33745)

* Add a draft section on credential types

* Credential types guide page

* Trim duplicated content from guide

* Apply suggestions from code review

Co-authored-by: Chris Mills <[email protected]>

* Add SMS server to OTP diagram

* Be explicit about mapping between types and interfaces

* Try a table for credential types

* Clarify OTP

* Update files/en-us/web/api/credential_management_api/credential_types/index.md

Co-authored-by: Hamish Willee <[email protected]>

* Update credental types diagram to emphasise that FederatedCredential is deprecated

* Update files/en-us/web/api/credential_management_api/credential_types/index.md

Co-authored-by: Hamish Willee <[email protected]>

* Update files/en-us/web/api/credential_management_api/credential_types/index.md

Co-authored-by: Hamish Willee <[email protected]>

* Update files/en-us/web/api/credential_management_api/credential_types/index.md

Co-authored-by: Hamish Willee <[email protected]>

* Move paragraph about deprecated FederatedIdentity credential

* Update files/en-us/web/api/credential_management_api/index.md

Co-authored-by: Hamish Willee <[email protected]>

* Use the same table of credential types in landing page

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Co-authored-by: Chris Mills <[email protected]>
Co-authored-by: Hamish Willee <[email protected]>