Open a preview URL in an embedded panel in Theia

[azatsarynnyy]

The issue based on the discussion #8974 (comment)

For now, a preview URL for a running command can be opened in a separate browser's tab only.
It'd be useful to have both options available: open URL in a separate tab or open URL inside Theia.

[azatsarynnyy]

To keep track of the progress more transparently here's the subtasks I plan to work on:

Preview URLs panel:

• Implement a Preview URLs panel, at the bottom, to display all the preview URLs. Temporary, a list of the URLs will be updated on each panel opening. Preview URLs panel can be opened via a widget on the status panel.
• A preview URL can be opened in a separate browser's tab.
• Preview URL list is synchronized with the running tasks automatically.

Preview panel - internal mini-browser:

• Implement a Preview panel, at the right, with an embedded mini-browser that can open a URL.
• Make it possible to open any preview URL in a Preview panel.

Preview URL notifications:

• Notifications are shown, at the top, as soon as a che-task is running and propose to open a related preview URL (internally or externally).

Preferences:

• By default, a user should be asked how to open a preview URL: internally or externally.
• A user should be able to choose a preview URL opening behavior in the Theia preferences:
  • ask everytime
  • always open internally
  • always open externally
  • never open a preview URL automatically

CC: @vparfonov @slemeur

[benoitf]

is it done through Theia plug-in webview ?

[azatsarynnyy]

@benoitf no, it's done through Theia extension view contribution

[slemeur]

must be with the plugin API

[azatsarynnyy]

Subtasks list has been updated after the discussion with @slemeur