Manage connected browsers and devices: Improve terms / translations

[b-pfl]

Hi all,

I just figured out, that https://docs.nextcloud.com/server/latest/user_manual/en/session_management.html would deserve being extended and updated:

1. Screenshots are outdated
2. The current interfaces shows 3 dots next to each device/browser where the user can do various actions that are not yet explained in the documentation, which leaves the open issues stated below:

• What the option "Allow filesystem access" does exactly, is not explained (assumption: Access to Files App, DAV etc. is allowed/blocked). Provide examples (e.g. if I use a CalDAV/CardDAV client - is it safe to not grant filesystem access?)
• The term used to wipe a device (at least in the German version) can create confusion: "Gerät löschen" (I assume this is what is described as "Wipe device" in English) would have the direct translation of "delete device", which could also just mean that this entry will be deleted (=password will be invalid) but nothing else. So maybe be more verbose (e.g. "Zugang entziehen und Gerät zurücksetzen" = "Revoke access and wipe device").
• The consquences of "wipe device" are not clear. What effect does this have on the various devices - does it only refer to the Nextcloud account and files (e.g. on a Smartphone) or would it do a factory reset on the phone? Should be clear both in the UI and the manual.

[joshtrichards]

Related: #1746

@b-pfl: I've updated the context of your report since #1746 already covers all of these except for the translation matter. I'm keeping yours for that aspect of things. Thanks for reporting and contributing to Nextcloud!