ServiceAccounts: Add secret scan service docs (#57926)

* add secret scanning docs

* update docs

* fix merge

* add revoke to docs

* add revoke to docs

* typo fix

* Apply suggestions from code review

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* add step by step instructions

* Apply suggestions from code review

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* prettier

* Update docs/sources/setup-grafana/configure-security/secret-scan.md

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>

* feedback

* Update docs/sources/setup-grafana/configure-security/secret-scan.md

* Update docs/sources/setup-grafana/configure-security/secret-scan.md

* Update docs/sources/setup-grafana/configure-security/secret-scan.md

Co-authored-by: Victor Cinaglia <victor@grafana.com>

---------

Co-authored-by: Christopher Moyer <35463610+chri2547@users.noreply.github.com>
Co-authored-by: Victor Cinaglia <victor@grafana.com>
(cherry picked from commit 3644ea65562fcddc4e8edf37e4a28051f1bf0e0f)

Co-authored-by: Jo <joao.guerreiro@grafana.com>