Wrap long lines to comply with flake8 E501 (#4985)

* Update flake8 settings

* Add poetry to isort namespace packages

* Ignore flake8 E501 for long test names

* Run automatic string formatting on tests

* Run automatic string formatting on src

* Fix typo "already exits"

* Ignore long URLs, hashes, and paths

* Fix in-line comments

* Fix in-line comments in tests

* Fix docstrings

* Ignore misc

* Fix f-strings in src

* Fix f-strings in tests

* Fix multi-line strings in src

* Fix multi-line strings in tests

* Fix some oddly autoformatted code

* Replace some strings by multi-line strings

* Revert namespace change

* Add black string processing to pre-commit

* Move black pre-commit config to pyproject.toml

* Autoformat install scripts

* Manual line wrapping for install scripts

* Disable black formatting for expected strings

* Replace strings by constant