[LOTP] Add git

# Description of the LOTP tool

`git` is often present in CI pipelines where repos are pulled in at build time. Being able to control `GIT_SSH` or `GIT_SSH_COMMAND` in the pipeline environment variables could result in code execution on build hosts where direct access to the host isn't possible.

[Ref](https://git-scm.com/book/en/v2/Git-Internals-Environment-Variables)

The issue names no implementation files or tests. Start by reviewing the LOTP tool's existing integrations and Git's environment-variable reference, especially GIT_SSH and GIT_SSH_COMMAND. Done should include a Git integration that demonstrates the intended pipeline execution behavior and has coverage for the supported variables.

Written by the indexing model from the issue text.