Account Notification Settings and Keywords

[langleyd]

Whats in this PR

• The ability to enabled/disable notifications across Default Notifications, Mentions and Keywords and Other (as in Figma)
• Updates the build setting to apply both room + account notifications
• Defines the 'PushRuleDefinitions' to very closely mirror how they are defined on iOS and Android
• It adds Chip,Chips, ChipInput components that render in a flow layout.
• The NotificationSettingsService and NotificationSettingsViewModel make use if combine to observe the push rule state of MxNotificationCenter. A nice off-shot of this is that the settings and keywords update 'live' to reflect any changes(say made from another client)since opening the screen.
• Removed swift-collections to simplify build for the moment. Adds the swift-collections library for use of the OrderedSet so that keywords don't jump around and are ordered in a sensible way for the end user.
• BorderedInputFieldStyle was added but not used in settings in the end. Keeping implementation though as will probably go into DesignKit.

What it loos like

Todos

• Add towncrier
• Fix chip text colour in dark mode

resolves #4469
resolves #4468
resolves #4467

[github-actions]

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[pixlwave]

There's a Riot/.DS_Store file that's been added. Should probably be removed.

[pixlwave]

More comments below ⬇️

There are a few more instances of using /* instead of /** for doc comments. Related question:
Do we have a convention of whether we use /// or /** */ in Swift? I've been using the former as Xcode generates it that way with the keyboard shortcut ⌘ ⌥ / but I think I prefer the multiline style visually.