Search and Replace for markdown fields

[aronmolnar]

The browser search doesn't work well for markdown fields, if text is not visible.

We're also missing a search and replace functionality.
Therefore, we will introduce a search&replace functionality. This will be available per markdown field (not for all fields in a finding a section).

[pure-nomad]

I would like this

[MWedl]

Implemented in https://github.com/Syslifters/sysreptor/releases/tag/2025.12