Log21

Moved some dictionaries to `__init__` methods.
`colors` in `Argparse.ColorizingHelpFormatter` class.
`_level_name` in `Formatters._Formatter` class and `level_colors` in `Formatters.ColorizingFormatter` class.
`sign_colors` in `PPrint.PrettyPrinter` class.
`colors` in `TreePrint.TreePrint.Node` class.

Improved type-hintings.

Switched from `setup.py` build system to `pyproject.toml`

Added `level_colors` argument to `log21.get_logger` function with will be passed to the formatter and allows
user to set custom level colors while making a new logger.
Also changed most `Dict` type hints to be `Mapping` and `list` to `Sequence` to make the functions more general
and less strict.

Added `extra_values` argument to `CrashReporter.Formatter` which will let you pass extra static or dynamic values to the
report formatter.
They can be used in the format string. For dynamic values you can pass a function that takes no
arguments as the value.

Shortened the usage syntax for the CrashReporters:

python
import log21

Define a ConsoleReporter object
console_reporter = log21.CrashReporter.ConsoleReporter()


This works with other `log21.CrashReporter.Reporter` subclasses as well.

Old syntax (still supported)
console_reporter.reporter
def divide_old(a, b):
return a / b


New Syntax
console_reporter.reporter
def divide_new(a, b):
return a / b



`console_crash_reporter` and `file_crash_reporter` are removed!