Support choice tables in dump subcommand

[karlding]

This change implements choice tables in the dump subcommand.

[coveralls]

Coverage increased (+0.04%) to 92.573% when pulling 387ea16 on karlding:support_choice_dump into 3c2aa1b on eerimoq:master.

[coveralls]

Coverage increased (+0.04%) to 92.568% when pulling 402dca6 on karlding:support_choice_dump into 3c2aa1b on eerimoq:master.

[eerimoq]

Please add a test where two signals in the same message have choices. I think I prefer the output to be:

Signal choices:

    Foo
        0 Disabled
        1 Enabled
        2 Other
        
    Bar
        0 On
        1 Off

[karlding]

Did you want me to add a command line test using tests/files/multiplex_choices.dbc, or is this along the lines of what you were thinking?

I wasn't sure if you wanted me to use that DBC, since there's another message inside besides the one with a multiplexed signal that has choice values.

[eerimoq]

You can create a new DBC-file, say files/dump_signal_choices.dbc, for dump signal choices testing. The file should contain a message with two signals, both with choices. Other dump scenarios are already covered by existing dump tests it seems.

[eerimoq]

Part of release 28.13.0, available on PyPI!