secrets maintainership

Opening a maintainership issue as I feel I'm ready to take this on for Secret Detection. I haven't had a substantial history of MRs, but I did work on the MR pipeline support, reviewed the integration-test migration, and am actively working on post-processing vendor integrations.

I picked up a lot of context from Zach too and generally understand the different contexts that Secret Detection works in, and the role of this analyser wrapper.