Improve project usage (#6)

1. Ignore unnecessary files, such as `pgcli` log/history, and extra `docker-compose` definitions.
2. Add `Makefile` with common tasks.
3. Add git pre-commit hook to ensure project is always properly formatted.
4. Add [`btree_gist`][0] extension to `postgres`.

Reviewed-on: #6

[0]: https://www.postgresql.org/docs/14/btree-gist.html

.gitignore

@@ -12,3 +12,6 @@
 erl_crash.dump
 *.ez
 wabanex-*.tar
+docker-compose.*.yml
+priv/docker/pgcli/history
+priv/docker/pgcli/log