Add progress reporting

[DL6ER]

What does this implement/fix?

Add a processing overlay when saving settings and add general progress bar for

1. login, and
2. saving settings

Example 1 (Login):

Example 2 (applying settings):

I would like to get some opinions: What is your general mood about this change? (in categories useless, hate it, like it, love it)

The timeout for the login is already dynamic (it takes as long as it takes) but the timeout for the settings is currently a hard-wired delay of 4 seconds (for demonstration purposes). We can make this dynamic by having FTL measure how long a restart really takes on a machine and sending this in the JSON response for using here.

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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[yubiuser]

I like it.

It needs to be dynamic as the restarting times depend on the hardware used (and maybe even delay.startup setting). And for the settings we need to decide how well it goes to together with the notification pop-up

[DL6ER]

delay.startup is only used within the first 180 seconds boot time, so it shouldn't really matter afterwards. Do we want to add extra handholding here?

The settings toast needs to be rephrased to something more "in-progressy". I don't think we should remove it altogether (but we could as we have the overlay).

[yubiuser]

delay.startup is only used within the first 180 seconds boot time, so it shouldn't really matter afterwards. Do we want to add extra handholding here?

No handholding. I forgot we added the 180 seconds at some point.

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I think the success toast should only fire after the progress animation finished, but at the same time.

[DL6ER]

I think the success toast should only fire after the progress animation finished, but at the same time.

On finish we reload the page, I don't think there is a possibility for the toast to survive this

[DL6ER]

The last commit should implement this without needing anything in addition from FTL.

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[github-actions]

Conflicts have been resolved.

[PromoFaux]

This is a good change, I like that when saving settings input is blocked until the page has reloaded. Without this PR, I can very easily trigger errors by attempting to change a setting again too quickly after I have hit save & Apply