Changes in this commit:

- AlwaysAllowSave config is gone. Saving is always permitted, unless in
  a read only document. Also changed the behavior in dbaccess to match
  sfx2.

- The toolbar save button is always enabled, to always give access to
  the dropdown. That's the case even in a read only document, except
  that it changes to DROPDOWNONLY, and the save as command icon+tooltip.
  In table/query designers we still disable the button in read only state.

- When the document is modified, the toolbar button gets a special icon
  to indicate that.

TODO:

- Icons for the document modified state are still missing. I added some
  fake links to Tango's links.txt in order to test the new behavior.
  These links shouldn't stay as-is in a production version!

Change-Id: I56c169bf48b78faaf53c2989ce8624f8297ffb6e
Reviewed-on: https://gerrit.libreoffice.org/20839Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>