Contact list: special separator list item added above each account group (except top one, when no active chats opened).

Account group layout: elevation decreased, contacts counter type made semi transparent and smaller, icon size decreased.

 GroupedContactAdapter programmatically elevation set removed.

ChatContactInflater simplified. Contact background set to grey_300 (was transparent) - to enable elevation.

Account group expander: offline contacts indicator always shown, conacts number shown on second line.

Merge remote-tracking branch 'origin/feature/new_contact_list_design' into feature/new_contact_list_design

Revert change that causes Xabber to crash when text selected (Fix: #384)

Note: this does not affect the red color of the action bar unless when
text is selected.

 Expander indicator icon changed and renamed, unused theme attributes removed.

Accounts and groups drawn in lighter colors.