Consider to implement new zserio type 'bits'

[mikir]

Currently, we have extern zserio type which means some array of bits. Because we have introduced new zserio type bytes (see #448), we might probably consider to introduce new zserio type bits as well. This seems to be more consistent in schema and more intuitive for users.

Then, we can deprecate extern keyword similarly to implicit array. This means that extern keyword will be disabled by default and users would be able to enable it by special command line option.

This issue has been created to open discussion about this idea.