Add calls to git_extract_argv0_path() in programs that call git_config_*

Add calls to git_extract_argv0_path() in programs that call git_config_*

Programs that use git_config need to find the global configuration.
When runtime prefix computation is enabled, this requires that
git_extract_argv0_path() is called early in the program's main().

This commit adds the necessary calls.

Signed-off-by: Steffen Prohaska <redacted>
Acked-by: Johannes Sixt <redacted>
Signed-off-by: Junio C Hamano <redacted>