- Supports toolbar-style, icon-size, orientation.
- Defaults are:
    toolbar-style = icons only
    icon-size = what's set in Tools > Options... for Sidebar/Notebookbar
    orientation = horizontal
- Remove no longer needed BigToolBox (use toolbar-style=both + icon-size=3 instead).

Change-Id: I185388255a351dfd6719a363b7e399bf36b0b25d
Reviewed-on: https://gerrit.libreoffice.org/34281Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>