This patch introduces a new function to send parameters
with UNO commands in UI Tests and adds a test which
uses the function to change the color of text in writer.

Change-Id: Ic687872ab826b50360e1bd042d9668a9f6ddbf63
Reviewed-on: https://gerrit.libreoffice.org/57857
Tested-by: Jenkins
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>