Update docs for 4.6.0

[nscuro]

• [x] Include changes to documentation of 4.5.x branch
• [x] Add Changelog for 4.6.0
• [x] Recurring tasks and configurability via #1542
• [x] Remove references to discontinued traditional WAR distribution
• [x] Remove outdated FAQ entries
• [x] Add documentation for usage with internal CAs
• [x] Update metrics documentation with authentication details (depends on https://github.com/stevespringett/Alpine/pull/416)
• [x] Clarify support status of MySQL and recommend usage of PostgreSQL and SQL Server instead
• [x] Update OSS Index docs with new usage terms as of 05.2022 (https://ossindex.sonatype.org/updates-notice)
• [x] Add migration guide for H2 v1 -> H2 v2
• [x] ~Add documentation for internal analyzer fuzzy matching~ (UI is self-explanatory)
• [x] Update OSV docs with instructions for ecosystem usage