Improved UI for replacing files such that share links are preserved

[madduck]

Initial Checklist

• I understand this is a feature request and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

Idea

This over from https://github.com/orgs/opencloud-eu/discussions/2493

Right now, if I share a file foo.pdf with a public link and find a mistake (as you would the second after sending the link to multiple people), in order to replace foo.pdf with the updated/fixed foo2.pdf, one has to:

1. locally rename foo2.pdf to foo.pdf, i.e. by copying it to a temporary directory;
2. upload that foo.pdf into the same OC folder as the shared foo.pdf
3. confirm the dialog that you want to replace the document, rather than keeping both.

This will cause the new foo2.pdf to be included in the foo.pdf history, and share links now serve the updated file.

This is a bit tedious. One solution would be to be able to upload the new file and then update the share link to point to the new file.

Here are two other ideas:

1. On upload of a file, ask the user to specify a filename, or select a file to overwrite;
2. In the details of an existing file, provide a "Replace" action that is just like uploading a new file, except that directly overwrites the existing file.

While I would love to see #2175 anyway, I think the second of these other ideas is actually both more intuitive and probably easier to implement.

Thanks for your consideration!