Adopt Compound Colours (#1086)

* Delete deprecated font tokens.

* Migrate from primaryContent to textPrimary/iconPrimary.

* Migrate from links to textLinkExternal.

* Migrate from secondaryContent to textSecondary/iconSecondary.

* Migrate from accent to textActionPrimary.

- Some uses changed to textPrimary or iconPrimary as necessary.
- Some manual tints removed now that that Sentry is fixed.

* Migrate alert to textCriticalPrimary/iconCriticalPrimary.

* Migrate from brand to textActionAccent/iconAccentTertiary.

* Migrate from background to bgCanvasDefault or text/iconOnSolidPrimary

* Migrate system to bgSubtleSecondary.

* Remove ElementUIColors and obsolete migrated colours.

* Migrate tertiaryContent/quaternaryContent/quinaryContent to Compound.

* Migrate bubblesYou/bubblesNotYou to use Compound.

* Update Compound.

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift

@@ -112,7 +112,7 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
         attributedString.enumerateAttribute(.backgroundColor, in: .init(location: 0, length: attributedString.length), options: []) { value, range, _ in
             if let value = value as? UIColor,
                value == temporaryCodeBlockMarkingColor {
-                attributedString.addAttribute(.backgroundColor, value: UIColor.element.quinaryContent as Any, range: range)
+                attributedString.addAttribute(.backgroundColor, value: UIColor(.compound._bgCodeBlock) as Any, range: range)
             }
         }
     }