Introduces script for updating horizon config

Since now, all custom murano settings stores at update_settings.sh
so it exempts from maintaining two config files at the same time.
This script intends to update developer config and production config.

Usage:

./update_settings

Arguments:
--input={FILE}    File to which Murano data will be added, if skipped horizon config from git repository will be downloaded
--output={FILE}   File to store the result file, if skipped it equals to the --input
--log-file={FILE} File to store murano dashboard logs instead of default output
--remove          Remove Murano data from the specified file

To update developer settings use the following command:
========================================================
update_setting.sh --output="muranodashboard/settings.py"
========================================================

Change-Id: I6e947f8887dfdcdc1f5651dd6acdc28bf9d924bf
Closes-Bug: #1332557
Implemets: blueprint separate-muranodashboard-config
Merge "Introduces script for updating horizon config"