mimeset: Style update
pkgman resolve-dependencies: Remove bogus option
mimeset: Change options style

* Use "--" prefix for long options and switch to getopt parsing. There's
  still compatibility support for "-apps" and "-all", but they are
  considered obsolete, now.
* Add short options "-a" for "--apps", "-A" for "--all", and "-h" for
  "--help".
Move MIME DB code back from registrar to src/kits/storage/mime

* Together with database_{access,support}.cpp it is built into a static
  library.
* Add new interfaces MimeSniffer and Database::NotificationListener for
  plugging in registrar specific functionality (the sniffer add-on
  support and the notification mechanism).
Refactor MIME DB access

* Add class DatabaseLocation. It contains a list of the MIME DB
  directory paths plus methods to access type files.
* Move all low-level MIME DB access functions from
  database_{support,access} to DatabaseLocation. All code that formerly
  used those now requires a DatabaseLocation object. In BMimeType and in
  the registrar the default object is used, but the low-level classes
  can now be reused with different locations.
* Move get_icon_data() from database_access to database_support and
  delete the former, which is now empty.
Pull class AppMetaMimeCreator out of CreateAppMetaMimeThread

Instead of using a BMimeType to set the MIME type properties, it
operates directly on the Database object, though.
storage/mime: Some host platform build fixes
mime/Database::Install(): Fix subtype without supertype case

If the supertype directory for a given subtype didn't exist yet, the
method would fail.
mime/database_support: Make buildable for host platform
Add private MIME DB classes to libbe_build

* This pulls in some more stuff, like libicon and agg which are also
  included in libbe_build, now.
* Update a few libbe_build classes and headers needed to get things
  building.
* This likely breaks the <build>mimeset build on Haiku.
mimeset: WIP to support custom MIME DB directories

Add option -m/--mimedb for specifying one or more directories to be
used as the MIME DB instead of the system MIME DB. Currently only works
with --apps and only non-recursive.

When fully implemented the new feature will be used in the build system
and on Haiku when building packages to generated the MIME DB entries for
applications, so those can be included in the same package. Furthermore
it will be possible to use the MIME DB the build system already
generates to identify files before packaging them.