Perhaps dconf can help. I`m enforcing proxy-usage:
# tree /etc/dconf
│ ├── site ← is generated by dconf update
│ └── site.d
│ └── 00_site_settings
# cat /etc/dconf/profile/user
# cat /etc/dconf/db/site.d/00_site_settings
After these changings, you have to activate them with [color=#0000FF]dconf update[/color]. It's immediately active for every user.
[color=#0000FF]dconf dump / > dconf-export[/color] and [color=#0000FF]dconf load / dconf-export[/color] may be helpfull for getting correct syntax.
You can easily deploy these folders with ansible to all active clients or use [color=#0000FF]ansible pull[/color] on bootup.