Drop DinD mode for SAST

What does this MR do?

Drop Docker-in-Docker (DinD) mode for SAST:

• remove the sast job used in DinD
• merge this job into .sast-analyzer when relevant

.sast-analyzer is the job template for the SAST jobs in non-DinD mode.

Warning! CI configurations that explicitly override the sast job become invalid since this job no longer exist. This is to be expected since we're dropping support DinD mode.

Tested in https://gitlab.com/gitlab-org/security-products/tests/go-modules/-/pipelines/184427977

See #220540 (closed)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation Documentation will be updated in a separate MR. See #220540 (closed)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team