Bug fix: rename `env.example` and `pre-commit-config.yaml`

[fgomez828]

Overview

This PR fixes a naming bug, renaming env.example to .env.example and pre-commit-config.yaml to .pre-commit-config.yaml for new-wagtail-app cookiecutter

Notes

These bugs caused the CI for the CRP project setup to fail.

To CI pass with these changes made, see the commit history for the main branch of the CRP app: https://github.com/datamade/crp-transparency/commits/main

I fixed linting errors manually since the pre-commit hooks weren't running.

Testing Instructions

• make sure the example env file and the pre-commit-config file are named with a . preceding them