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/SwiftUI/Views/AvatarHeaderView.swift

@@ -34,13 +34,13 @@ struct AvatarHeaderView<Footer: View>: View {
                                 imageProvider: imageProvider)
 
             Text(name ?? id)
-                .foregroundColor(.element.primaryContent)
+                .foregroundColor(.compound.textPrimary)
                 .font(.compound.headingLGBold)
                 .multilineTextAlignment(.center)
 
             if let subtitle {
                 Text(subtitle)
-                    .foregroundColor(.element.secondaryContent)
+                    .foregroundColor(.compound.textSecondary)
                     .font(.compound.bodyLG)
                     .multilineTextAlignment(.center)
             }