feat: auto-fill active domain and enhance validation
- Auto-populate domain input with the current page's hostname when opening the popup
- Enhance domain validation to reject local/private IPs, protected URLs, and extensions
- Show descriptive error message for protected/local domains
- Reject IP addresses (IPv4/IPv6), localhost variants, and private ranges (192.168.x.x, 10.x.x.x, 172.16-31.x.x)
- Improve UX by preventing users from adding invalid domains to lists

Feat: Added option to switch between add-on operation modes:
- Excluded only list - It will work on all supported websites by default. Add domains to this list to block it on them.
- Included only list - Add websites' domains to this list to activate it on them. The add-on will make DOM changes only on those domains added to this list.

Fix: Instagram divs with no class value are clickable again - 'Messages', 'Notifications'...
Fix: Instagram overlays are up a little bit (tags and sound buttons).

Tech stuff:
- Better documentation/comments/code organization.
- Manifest update: No data collection.

Add Instagram support for now.

And no, it doesn't allow you to download videos from it.

Some important notes:
Instagram changes its code faster than most sites, may break my current code kinda easily.
"Tags" button on videos leave a paint trail from the initial position it was placed. I had to move it a bit so it wouldn't overlap with the now active video controls.

Fix - Removes 9gag.com videos overlays -> sound button, video duration.