Add version info

[Boldewyn]

This changeset adds version information to two places:

• a new command version prints the current version of the tool
• during runs the steps write their used version into the workspace DB as log messages with level info

The clean-up of phpunit files is unrelated, but seemed not to merit its own pull request.

[DvogelHallowelt]

In general a good solution but do we really need to add the information for each step to the database?
Keep in mind analyze and extract do run multiple times fi more then one spaces are migrated. converter always runs multiple times.

In my opinion it would be enough to add this in the compose step to the database and the log files.

[Boldewyn]

Yes, agreed, it is not useful to fill the logging table with many message instances for a single run.

OTOH for reporting, long-running migration projects, and general accountability it would be good, if every invocation of analyze, extract, convert and compose would leave exactly one message. I’ll try to move the logging in the analyze and extract steps to a place where it will be called only once per command execution.