Support for UNIMARC

Does koha-testing-docker support UNIMARC at this stage?

Adding either UNIMARC or unimarc to the env/defaults.env file didn't seem to make any difference.

When trying reset_all_unimarc it hangs at the last line (see #107 (closed)):

> Inserting /kohadevbox/koha/installer/data/mysql/en/marcflavour/unimarc/mandatory/authorities_normal_unimarc.sql...
> Inserting /kohadevbox/koha/installer/data/mysql/en/marcflavour/unimarc/mandatory/unimarc_framework_DEFAULT.sql...
> Setting the MARC flavour on the sysprefs...
> Setting Koha version to 18.0600035...
> Running [sudo koha-shell kohadev -p -c 'PERL5LIB=/kohadevbox/koha:/kohadevbox/qa-test-tools perl /kohadevbox/misc4dev/create_superlibrarian.pl --userid koha --password koha ']...
> Running [sudo koha-shell kohadev -c 'PERL5LIB=/kohadevbox/koha:/kohadevbox/qa-test-tools perl /kohadevbox/misc4dev/insert_data.pl --marcflavour UNIMARC']...
> There is no records data for UNIMARC yet at /kohadevbox/misc4dev/insert_data.pl line 50.