use standard project layout and tool config across all pallets and
pallets-eco projects
* add issue templates
* add dependabot grouped updates for actions and pypi
* add lock inactive closed issues workflow
* add publish workflow with slsa and trusted publishing
* simplify tests workflow matrix
* simplify docs config.py
* show license in docs
* use pip-compile to pin development dependencies
* rename test to tests
* add .editorconfig
* simplify .gitignore
* add pre-commit hooks (will run formatters in a subsequent PR)
* pin os and python in .readthedocs.yaml
* update license with original commit date and pallets-eco
* use pyproject.toml and flit_core instead of setuptools
* only declare flask dependency
* add config for mypy and pyright (will add typing in a subsequent PR)
* readme is markdown
* add pallets-eco message to readme
* remove install and docs links from readme
* add style, typing, docs tox envs
* use faster wheel building tox config
* add tox command to update dev dependencies
Update to the newer PyPI / python packaging metadata file structure.
A lot of this was cribbed from how [`Flask`](https://github.com/pallets/flask) itself
exposes its metadata.
