Update documentation for automountServiceAccountToken hardening
General MR
Summary
Related to https://repo1.dso.mil/big-bang/bigbang/-/issues/1857
Documents usage of the mutating Kyverno policy update-automountserviceaccounttokens to harden ServiceAccounts in this Package/namespace.
Also fixes some typos/outdated information in DEVELOPMENT_MAINTENANCE.md
Edited by Justen Mehl