This ensures that any newly created SyncedCatalogComponent-based
catalog is enabled by default at startup.

+ Call the fake catalog for internet-resolved objects as
  "_Internet_Resolved". The prefix "_" has the dual purpose of making
  it look "internal", and making it appear at the end of the sorted
  list of catalog names in the settings dialog. The name is more
  meaningful to the user.

  Also, we hold this name in a string that is initialized in the
  constructor, as it is used in multiple places -- makes it easy to
  change, but we should refrain from doing so as it will result in a
  junk catalog remaining in the skycomponent database.

+ Allow enabling / disabling the "_Internet_Resolved" catalog like any
  other catalog in the settings dialog. This is different from
  enabling/disabling resolution, which is controlled by a checkbox
  below (introduced in one of the previous commits)

Adding SyncedCatalogComponent, a new SkyComponent that loads a custom
catalog, and can also add objects synced with the database.

Custom catalogs are stored in an SQLite database. CatalogComponent
loads these into memory and handles their rendering etc. This new
subclass also allows adding of new objects at run time. The new
objects are written to the database and also available at run-time,
and hence the "synced".

Typically, one would not add objects to a well-known catalog, so
SyncedCatalogComponent will usually be used with "fake" catalogs, just
lists of objects that we put into a catalog with some name and assign
IDs to the objects, that are completely unofficial. Since the catalogs
are 'unofficial', the Catalog_Prefix + Object ID name doesn't mean
anything, so we try to hide it.