Remove SAST Analyzer SAST_GOSEC_CONFIG variable

Release notes

Problem to solve

SAST_GOSEC_CONFIG has been deprecated in favor of custom rulesets. We need to remove it from the product.

Proposal

• Remove CLI flag from gosec analyzer. gitlab-org/security-products/analyzers/gosec!106 (merged)
• Update documentation to remove references to the variable. | !63518 (merged)
• Update both SAST.gitlab-ci.yml and Secure-Binaries.gitlab-ci.yml to remove references to the variable and bump SAST_ANALYZER_IMAGE_TAG | !63547 (merged) | !63546 (closed)
• Update integration tests to use custom rulesets.