[Feature Request] Allow _GIT_* variables to be passed as command-line args

[slw07g]

Allow _GIT_* variables to be passed as command-line args rather than having them set as environment variables.

git-quick-stats/git-quick-stats

Lines 176 to 193 in 71d414e

	ADDITIONAL USAGE
	You can set _GIT_SINCE and _GIT_UNTIL to limit the git time log
	ex: export _GIT_SINCE=\"2017-01-20\"
	You can set _GIT_LIMIT for limited output log
	ex: export _GIT_LIMIT=20
	You can set _GIT_LOG_OPTIONS for git log options
	ex: export _GIT_LOG_OPTIONS=\"--ignore-all-space --ignore-blank-lines\"
	You can exclude directories or files from the stats by using pathspec
	ex: export _GIT_PATHSPEC=':!pattern'
	You can set _GIT_MERGE_VIEW to view merge commits with normal commits
	ex: export _GIT_MERGE_VIEW=enable
	You can also set _GIT_MERGE_VIEW to only show merge commits
	ex: export _GIT_MERGE_VIEW=exclusive
	You can set _MENU_THEME to display the legacy color scheme
	ex: export _MENU_THEME=legacy
	You can set _GIT_BRANCH to set the branch of the stats
	ex: export _GIT_BRANCH=master"
	}

[igbanam]

The way I use this is almost like command line variables; but "pre" command line variables

_GIT_SINCE="2023-01-01" _GIT_UNTIL="2023-12-31" git-quick-stats -a

I think this keeps the git-quick-stats API clean and focused enough