MBS-6068: initial SQL for removing _name tables

This does not yet include an upgrade script, any test fixes, or any perl
changes except for export and import scripts, and deleting the
now-pointless UnusedNames script.
MBS-6068: purge all git-greppable references to name_table
MBS-6068: remove all git-greppable references to find_or_insert_names
MBS-6068: first pass of Data::Artist
MBS-6068: remove remaining references to _table_join_name
MBS-6068: first pass of Data::Label and Data::Work
MBS-6068: first pass of Data::Track
MBS-6068: first pass of Data::Recording
MBS-6068: first pass of Data::Release
MBS-6068: first pass of Data::ReleaseGroup
MBS-6068: first pass of Data::ArtistCredit
MBS-6068: first sweep of the rest of Data::, excluding Search
MBS-6068: loose ends in Data::Medium and Data::RecordingPUID
Merge branch 'master' into mbs-6068-name-tables
MBS-6068: purge artist_name from webservice.sql
MBS-6068: purge release_name from webservice.sql
MBS-6068: purge label_name from webservice.sql
MBS-6068: purge track_name from webservice.sql
MBS-6068: purge work_name from webservice.sql
MBS-6068: fix InsertDefaultRows