Use uppercase country codes in catalog names.

nielx+pulkomandy: With the switch from Pootle we switched to the correct
representation of country codes by using lang_COUNTRY (instead of lang_country).
Haiku did not respect that yet and instead always looked for lower case country
codes, thus not finding all the hard work of the pt_BR team.

Other translations currently affected are en_CA and en_GB, though these are not
actively maintained.

+alpha4

Cleanup BCatalogAddOn.

* rename BCatalogAddOn to BCatalogData, since it doesn't represent an
add-on, but rather the catalog data provided by an add-on
* move BCatalogData out of Catalog.{h,cpp} into its own header and
implementation file
* drop BCatalogData::MarkForTranslation() methods, they're not needed
* drop BCatalog::GetNoAutoCollectString() methods, they're not being
used anywhere
* cleanup the B_TRANSLATE_... macros somewhat
* add versions of the B_TRANSLATE_MARK_... macros that are meant to be
used in void context (when the string isn't being used by the program,
just meant to be picked up by collectcatkeys).
* adjust several apps to use B_TRANSLATE_MARK_..._VOID where needed
* adjust users of BCatalogAddOn accordingly

Use uppercase country codes in catalog names.

nielx+pulkomandy: With the switch from Pootle we switched to the correct
representation of country codes by using lang_COUNTRY (instead of lang_country).
Haiku did not respect that yet and instead always looked for lower case country
codes, thus not finding all the hard work of the pt_BR team.

Other translations currently affected are en_CA and en_GB, though these are not
actively maintained.

+alpha4

Cleanup BCatalogAddOn.

* rename BCatalogAddOn to BCatalogData, since it doesn't represent an
add-on, but rather the catalog data provided by an add-on
* move BCatalogData out of Catalog.{h,cpp} into its own header and
implementation file
* drop BCatalogData::MarkForTranslation() methods, they're not needed
* drop BCatalog::GetNoAutoCollectString() methods, they're not being
used anywhere
* cleanup the B_TRANSLATE_... macros somewhat
* add versions of the B_TRANSLATE_MARK_... macros that are meant to be
used in void context (when the string isn't being used by the program,
just meant to be picked up by collectcatkeys).
* adjust several apps to use B_TRANSLATE_MARK_..._VOID where needed
* adjust users of BCatalogAddOn accordingly