feat: use check updates modal for update available in navbar

[szwabodev]

• added /api/health endpoint for frontend app
• changed docker service restart command not to be awaited during server update
• navbar will now open the updates modal (with version information, releases link, etc.) intead of directly asking for confirmation of update
• refactored updates modal to allow using updateData which is already fetched
• updated confirm update modal to inform that using the panel is not possible during update
• updated confirm update modal to not allow closing the modal, and inform about update being done
• fixed checking if server update finished by using health endpoint instead of waiting for docker service restart command which doesn't properly finish due to restart of the whole app causing an error to be thrown instead
• removed ping icon from "new version available" section (I think 2 pinging icons in same visible component is too much :D)

Clicking "Update available" in navbar opens this modal now:

Added information about not being able to use panel during update:

Closing the modal is blocked until server update is finished:

Server update success: