Promote mobsf and mobile SAST to general availability
<!-- This template is a great use for issues that are feature::additions or technical tasks for larger issues.-->
### Proposal
Our [mobsf analyzer](https://gitlab.com/gitlab-org/security-products/analyzers/mobsf/) 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](https://gitlab.com/gitlab-org/gitlab/-/blob/bf6ce785ed117d2ce99183067f8f22ddc7c150c2/lib/gitlab/ci/templates/Security/SAST.gitlab-ci.yml#L180)
1. Add to Configuration UI
1. 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
epic