BAppFileInfo: Coding style update

Also remove doxygen comments.
BAppFileInfo: Add method versions that don't touch the MIME DB

Add SetSupportedTypes() and SetIcon[ForType]() versions with an
additional bool updateMimeDB parameter. If false, the method doesn't
update the MIME DB entries for the type.
libbe_build: Sync BAppFileInfo
MimeInfoUpdater: Don't touch the MIME DB

Use the new SetIconForType() and SetSupportedTypes() versions and
request the MIME DB not to be updated. This changes the
update_mime_info() and mimeset (without -a/-A) behavior in that they
only modify the (application) file attributes, now. Addresses #10453.