feat: (144) Add Directory Support -d --directory

[keikoskat]

#144

Example commands using the new directory option:

secureli scan --directory /absolute/path/to/a/git/directory
secureli scan -d ./relative/path/to/a/git/directory
secureli init -d ./relative/path/to/a/git/directory
secureli update --directory /absolute/path/to/a/git/directory

[github-actions]

PR title failed to match (chore|style|test|feat|fix|docs): .+

All good!

[chrisba11]

Looks good, per our review this morning.