TLS 1.3 support and minor fixes

This release adds TLS 1.3 support, and fixes a variety of bugs.

Features:

• Enabled support to connections using TLS 1.3.

Fixes:

• URL view on the Dashboard should now be visually consistent with URL view shown in site settings
• Fixed an issue where site icons were not displaying in the site list
• Using _disable_add now properly prevents editors from creating new items
• Fixed a bug that caused the Visual Editor to sometimes get stuck on "Uploading Changes…"
• Fixed a bug causing the editor to sometimes get stuck on "Collecting Changes" after creating a new post
• Updated the error codes returned from invalid html form submission
• Fixed an issue with image rotation in specific circumstances on Chrome
• Minor Quality of Life improvements
• Minor UI touch-ups