Changing lint levels for different Dataverse versions

[HenningTimm]

Rule e004 (trailing whitespaces) was dangerous in Dataverse <=6.4, but is fixed through a change in Dataverse now (cf. #23 , IQSS/dataverse#10688).

Currently, this software has no nice way to accord for this. By default, e004 will become a warning, however there is no way to increase a lint level via parameters. Some possible solutions are:

1. Add a --fail or --error that behaves similarly to --warn and --skip. This should be implemented either way.
2. Add a config file that defines default behaviors for the current Dataverse version and other profiles for different versions.
3. Add a parameter to specify a Dataverse version and select a predefined set of parameters accordingly.

I tend towards solutions 1. and 2., since keeping 3. up-to-date would break the scope of this project.

[HenningTimm]

1. was implemented in 93f0507