Decide how to handle SAML (and SCIM) troubleshooting docs

Problem to solve

There is a lot of overlap between self-managed and SaaS SAML. While the feature is different, troubleshooting is almost identical.

Further details

Our docs has content on SAML (and SCIM) troubleshooting in a number of places:

1. SM Auth page has how to change apps: https://docs.gitlab.com/ee/administration/auth/#change-apps-or-configuration
2. SM SAML page: https://docs.gitlab.com/ee/integration/saml.html#troubleshooting
3. SaaS SAML page: https://docs.gitlab.com/ee/user/group/saml_sso/#troubleshooting
4. SaaS SCIM page (yes this is a different feature, but again, troubleshooting is similar): https://docs.gitlab.com/ee/user/group/saml_sso/scim_setup.html#troubleshooting
5. "Troubleshooting Group SAML and SCIM" page (which has nothing about how to troubleshoot): https://docs.gitlab.com/ee/administration/troubleshooting/group_saml_scim.html

Proposal

1. Move all SAML troubleshooting content to one page. File to live under SAML SSO (SaaS) folder
2. Clearly separate anything that is self-managed or SaaS specific.
3. Remove anything overlapping from SCIM troubleshooting and reference SAML troubleshooting page.

For screenshots page, see #364599 (closed)

Who can address the issue

Support & TW