Dewi-core

- Node: load creates Node/NodeList if possible for unknown members
- Node.create() accepts only kwargs
- logger: use Node's create() method
- use type annotations w/o typing module, requires python 3.10+
- requires Python 3.10+

- Add Node.create() factory method
- TestCase: add lowercase alias method, assert_no_logs
- logger: ensure that a Logger with a specific name is created only once
to avoid log entry multiplication

- Fix application's --cwd parameter; change directory as needed
- Add support of multiple loggers based on the Application's logger config
using create_logger_for()
- global logger is '_logger', shouldn't be used directly

- Application: updated to work with click 8.1.0 (and also with 8.0.x).

- Application:
* add optional description parameter
* print cmd name if exception occurs during arg registration
- remoting: use click, too (remained as special case)
- OptionContext:
* add nestable groups
* add back the 'choices' option from argparse, replaced internally
in add_XXX methods
* required mutually excl groups: better error msg if an option is missing
- show runtime of the command at the end if env var set: DEWI_SHOW_RUN_TIME=1

- follow-up a change in pyyaml, CLoader may be Loader without C
- small fix for Python 3.10 (collections -> collections.abc.Mapping)