feat(desktop): add OCA.Talk.Settings API to customize and manage settings

[ShGKme]

☑️ Resolves

• Primary for: Desktop settings talk-desktop#27
• Talk Desktop demo PR: wip: Talk Desktop Settings talk-desktop#792

Adds new public API to register custom settings sections for Talk app using Web Components.

type TalkSettingsSection = {
	/**
	 * Section internal ID
	 */
	id: string
	/**
	 * Section visible name
	 */
	name: string
	/**
	 * WebComponent's (custom element's) tag name to render as the section content
	 */
	element: string
}

window.OCA.Talk.Settings = {
	/**
	 * Open settings dialog
	 */
	open()

	/**
	 * Register a custom settings section
	 * @param section - Settings section
	 */
	registerSection(section: TalkSettingsSection)

	/**
	 * Unregister a custom settings section
	 * @param id - Section ID
	 */
	unregisterSection(id: string)
}

Screenshots with demo

🏁 Checklist

• 🌏 Tested with Chrome, Firefox and Safari or should not be risky to browser differences
• 🖥️ Tested with Desktop client or should not be risky for it
• 🖌️ Design was reviewed, approved or inspired by the design team
• ⛑️ Tests are included or not possible
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required

[Antreesy]

Changes look good, hope we don't have to change it later
Tested

[DorraJaouad]

LGTM

[ShGKme]

/backport to stable30