Remove the per-project files so we don't have to
keep them in sync. GitHub's UI links to everything
except the contributing guide, so add a section
about that to the readme.
(cherry picked from commit 60a11a730e)
fix tox to test examples again
add detox tox env for faster testing
clean up makefile, add tox target
add extra group for installing dev requirements
clean up contributing doc, build with docs
expand issue template
add pull request template