1.2.0.0

Visitor Map 1.2.0.0: OMP support

The plugin already ran on OMP: the core keeps the same geographic statistics
and the same usage log, and the plugin reaches the context through the
application's context DAO and public file manager. What changes:

- locale-omp/: the nine texts that name the journal, its articles and OJS,
  saying press, book and OMP in the 38 languages; registered above the
  plugin's own locale only when the application is OMP, so no core key is
  touched and Custom Locale still wins
- tests: the map file is looked for in the public folder of the running
  application; the application gets its own texts; locale-omp covers every
  language with the same keys and placeholders
- CI: OMP on MySQL and PostgreSQL in the matrix
- README: OJS and OMP