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.

plugins/git/subcommands/report

@@ -1,6 +0,0 @@
-#!/usr/bin/env bash
-source "$PLUGIN_AVAILABLE_PATH/git/internal-functions"
-set -eo pipefail
-[[ $DOKKU_TRACE ]] && set -x
-
-cmd-git-report "$@"