Feature/3423/show upload progress

[marcoambrosini]

fix: #3423

requires: nextcloud-libraries/nextcloud-vue#1196 and nextcloud/server#21810

[danxuliu]

Please extract commit "Fix spinner position" to its own pull request for easier backporting, as the bug is present too in stable19 (I have not checked stable18). Also please fix (in that pull request is fine) the message date being shown in temporary messages if they are tall (to test just send a message that has several new lines, you will see that the temporary message shows "1:00 AM" as its date).

The temporary message for files being uploaded has a couple of issues:

• When the temporary message is added the message list is not scrolled to the bottom.
• When the upload finishes the temporary message is removed, and when the message list is received again from the server the uploaded file is shown, which causes some flickering. I guess that the file upload message sent by the server should include a referenceId parameter to solve this (and the explicit deletion of the temporary message after the file is uploaded should be removed), although I have not checked.

When a file is uploaded an Vue is built in development mode there is a validation error shown in the browser console, although I guess that it is fixed by nextcloud-libraries/nextcloud-vue#1218 and thus it will be gone once a new nextcloud-vue version is released. As it is just a validation issue in development mode I would be fine merging this pull request before that is fixed.

Finally I have also noticed that in Chromium it is not possible to upload the same file twice in a row, but it happens too in master, it is not related to this pull request. In Firefox it works fine. Fortunately it should not be a very common use case ;-)

[nickvergessen]

When the upload finishes the temporary message is removed, and when the message list is received again from the server the uploaded file is shown, which causes some flickering. I guess that the file upload message sent by the server should include a referenceId parameter to solve this (and the explicit deletion of the temporary message after the file is uploaded should be removed), although I have not checked.

I will have a look if we can hack this somehow in on the share request on the backend. So we will do this as a follow up.

[nickvergessen]

Reference id handled in #3948