Promote mobsf and mobile SAST to general availability

Proposal

Our mobsf analyzer is currently enabled behind the SAST_EXPERIMENTAL_FEATURES flag. We should establish an exit criteria and timeline for promoting this to general availability and enabling by default

1. Remove SAST_EXPERIMENTAL_FEATURES conditional from template
2. Add to Configuration UI
3. Update docs

Considerations

• conformity to standard analyzer architecture
• conformity to standard analyzer capabilities
  • alpine base image https://gitlab.com/gitlab-org/gitlab/-/issues/301062
  • feature support; i.e. customized rulesets
• offline support