Dialog Service: Select Multiple Projects Dialog

[tjcouch-sil]

As an extension developer, I want to be able to ask the user for multiple projects using existing dialogs in Platform.Bible so I can open a webview with multiple project connected (like Text Collection).

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Add a Select Multiple Projects dialog to the dialog service

• Share UI with the Open Multiple Projects dialog Projects: Create stubbed Open Multiple Projects dialog #360
• Provide title, prompt, etc
• Returns promise to the selected project IDs
• Call with something like papi.dialogs.getMultipleProjects or selectMultipleProjects or something

Very similar to the Select Projects dialog but with multiple projects returned

Depends on #388

[tjcouch-sil]

Split off from #388