LP#1673857: schema, IDL, library settings & perms for copy tags

LP#1673857: schema, IDL, library settings & perms for copy tags

Three new tables are added to store copy tags:

* config.copy_tag_type

  Defines types that can be used for distinguishing between
  classes of copy tags when searching the catalog. The
  seed data includes a 'bookplate' type by default. The new
  permission ADMIN_COPY_TAG_TYPES controls C/U/D access to this
  table.

* asset.copy_tag

  The actual copy tag values. Copy tags have both labels and values,
  and since at least one interface allows creating copy tags
  on the fly, a trigger will set the value of a new tag
  to its label if the value is null. asset.copy_tag also has a flag
  for setting whether given tag should be searchable (and visible)
  in the public catalog or not. The new permission ADMIN_COPY_TAG
  controls C/U/D access to this table.

* asset.copy_tag_copy_map

  This stores the link between copies and their tags. Only the
  UPDATE_COPY permission is required in order to set tag mappings.

The new library setting is opac.search.enable_bookplate_search, which
controls whether or not to display a "Digital Bookplate" entry in the
catalog search fields dropdowns.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>
Signed-off-by: Josh Stompro <stomproj@larl.org>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>
Conflicts:
	Open-ILS/src/sql/Pg/950.data.seed-values.sql

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>