* Moved cloning functionality into its own `cloneSrc` function
* Start writing compiled data into CWD instead of user home dir, in
order to prevent mangling between projects
* Introduce `LEI_LUAU_SRC` variable to allow users to provide a path to
an already checked out luau source dir; when not set, a temporary
directory is created and removed after compilation
* Do not panic if cmake build dir already exists, just skip creating in
that case
* Automatically set required C includes path for commands
* Added warning to commands if the `.lei` directory is not present in
the gitignore
