Custom/Coloured Favicons

Problem/Justification
I have multiple TrueNAS systems and when the tabs are compressed down to just favicons I can’t tell them apart since upgrading the old one to Fangtooth with the favicons now being the same again.

Impact
Adding the option to either colour the favicon or upload a custom favicon would allow for easier identification of the specific TrueNAS instance.

User Story
I get another TrueNAS box for offsite backup, when navigating around my environment I can click on the White Truenas tab for production and the Blue Truenas tab for backups, reducing the chance for accidentally making changes on the wrong machine and increasing the speed of finding open tabs to a specific instance.