docs : Add sphinx for handling documentation

Edit gitignore by ignoring the docs/build directory
Add sphinx dependencies to pyproject
Add docs folder

pyproject.toml

@@ -20,3 +20,10 @@ packages = [{include = "unisync", from = "src"}]
 [build-system]
 requires = ["poetry-core>=2.0.0,<3.0.0"]
 build-backend = "poetry.core.masonry.api"
+
+[dependency-groups]
+docs = [
+    "sphinx (>=9.1.0,<10.0.0)",
+    "sphinx-rtd-theme (>=3.0.2,<4.0.0)",
+]
+