TANGO: add icons for .uno:SoureView and .uno:WebHtml

Change-Id: I6601d40f86d7abdaffef0cb0167e84efa54548ba
Reviewed-on: https://gerrit.libreoffice.org/13192
Reviewed-by: Yousuf Philips <philipz85@hotmail.com>
Tested-by: Yousuf Philips <philipz85@hotmail.com>
(cherry picked from commit 7232dc4baf3575dc300421a13b41e05d7b92dc5d)
Reviewed-on: https://gerrit.libreoffice.org/13195