feat: port git :report subcommand to golang

The bash :report implementation for the git plugin is replaced with a compiled golang binary. Property, computed and global keys are collected in parallel, while the sha and last-updated-at keys still shell out to git and stat the deploy branch ref so their values are unchanged. The non-report git helpers such as fn-git-cmd and the computed deploy-branch and keep-git-dir getters remain in place for the build pipeline.

go.work

@@ -19,6 +19,7 @@ use (
 	./plugins/cron
 	./plugins/docker-options
 	./plugins/domains
+	./plugins/git
 	./plugins/haproxy-vhosts
 	./plugins/logs
 	./plugins/network