docs: developers boilerplate

DEVELOPERS.md

@@ -0,0 +1,13 @@
+# TODO: link to here from sphinx docs
+
+# Fetching submodules
+git submodule update --recursive --init
+
+# Installing dev dependencies
+uv pip install -e .[dev]
+
+# Building documentation
+sphinx-build -M html source build -a
+
+# Building installer package
+TBD