perf: Prepend the app as a whole

[nickvergessen]

• We noticed that on Talk quite many assets are loaded before Talk
• So we tested to add prepend perf: Load talk UI earlier spreed#16375
• But turns out that only prepends the file within talks list
• It still loaded the 25 reference widgets app in alphabetical order before the main UI of Talk 🙈

Before	After

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[susnux]

Isnt this on purpose?
So that you can prepand a script in your scripts list.
But this now does not prepand the script in the app scripts but it prepands it before all other scripts of other apps.

For me this sounds like a different use case where we should maybe have a order or priority option.

So before: use prepand to unshift a script in your app scripts (make a higher priority script for your app).
After: prepand increases the priority of all scripts of that application having side effects on all other apps.

[susnux]

This changes the behavior from unshift a script in the list of your scripts (e.g. because you need specific order) to give your app higher priority over all other apps.

I do not think that is bad, but in that case please add a documentation string to the prepand attribute that it will prepand all scripts of that app in the global scripts list.

[nickvergessen]

Isnt this on purpose?
After: prepand increases the priority of all scripts of that application having side effects on all other apps.

Currently it's ordered "fifo". Since Talk/Spreed is rather late in the alphabet all other apps got triggered already even if they are neither the main page nor important for the content are loaded already via the RenderReferenceEvent event.

If talk similarly to calendar adds a single addScript in its boot() method, ALL files of Talk are in the front block:

Before	After

So yes, the "after" you outline is exactly what we want to achieve. On call/$token URL, after core for the main headers, the talk-main.js should be the next thing loaded, not 25 reference widget apps first. We can also add a different prepend parameter, so we can load talk-main.js prepended app wise and the rest of talk at the old position, but we need a way to get talk-main.js to be earlier.

[susnux]

Then as said: I think this is a good change.
But to prevent someone else has the same questions later could you add a small doc string on the docblock for that parameter?