Rename Resolution to Mag (in UI and code where possible)

[philippotto]

Detailed Description

In code and UI, we should switch to the term Mag everywhere for consistency reason. Quoting @fm3, there should be strategic tooltips which explain the concept.

Context

https://scm.slack.com/archives/C5AKLAV0B/p1695737597207699

[fm3]

@normanrz @hotzenklotz this is your chance to veto this if you think the term Mag is too obscure ;)

(Though i think at the terminology meeting that resulted in this document https://docs.webknossos.org/webknossos/terminology.html we also agreed on Mag)

[normanrz]

I think it is more important to be consistent. So, yes for Mag.