[eryntools] Add a dotfiles package to eryntools

Implement a utility for finding the dotfiles repo. It assumes ~/.dotfiles unless an override is given.

Python/eryntools/src/eryntools/dotfiles/__init__.py

@@ -0,0 +1,32 @@
+# Eryn Wells <eryn@erynwells.me>
+
+from os.path import expanduser, expandvars, isdir, join
+from typing import Optional
+
+
+def find_repository(path: Optional[str] = None) -> Optional[str]:
+    '''Find the dotfiles repo.'''
+
+    _DEFAULT_CANDIDATE_PATHS = [
+        '~/.dotfiles',
+    ]
+
+    candidate_paths: list[str] = []
+    if path:
+        candidate_paths.append(path)
+    candidate_paths.extend(_DEFAULT_CANDIDATE_PATHS)
+
+    for path in candidate_paths:
+        path = expanduser(path)
+        path = expandvars(path)
+
+        if not path_is_git_repository(path):
+            continue
+
+        return path
+
+    return None
+
+
+def path_is_git_repository(path: str) -> bool:
+    return bool(path) and isdir(path) and isdir(join(path, '.git'))