UX / UI: Make upload button more visible on upload enabled shares

[ThomasLeister]

Steps to reproduce

1. Create upload enabled shared folder and share link to friends / ...
2. Ask non-Nextcloud experienced friends to upload files

Expected behaviour

Friends should be able to find upload button quickly

Actual behaviour

Friends spend too much time to figure out how to upload stuff

Suggestion

Nextcloud experienced users will find the "Create folder" or "upload file" button quite quickly. Users who are not used to Nextcloud seem to have a hard time figuring out how to upload files, because the UI does not really indicate that at first sight. This has happened to my friends / relatives several times, and it's always frustrating to explain to each single person. They do not expect the file upload in a somehow hidden submenu. Upload should be obvious even to my grandma.

Better: On upload enabled "via link" shares, display a big, colored button for file upload / folder creation.

[ghost]

It would make sense to add this. Saves us from potential Discussions about "Oh my God Nextcloud is so difficult" :D

[nextcloud-bot]

GitMate.io thinks possibly related issues are #434 (New sharing UI), #5439 (Add upload button to shared upload-links), #5916 (UI problem in sharing options), #8343 (Share by link (read-only): upload button), and #6794 (No possibility to upload images to publicly shared gallery with upload enabled).

[MorrisJobke]

We have an ongoing discussion about the upload button in general and how to integrate it into the sharing page in #4011. Let's join forces on this topic in there.