Feature to add comment when importing logger data

[HenrikSpa]

It would be useful if the user could set a comment for the logger data when importing using Diveroffice import. The user would probably want to add a comment like "Data from zzzz" or something similar.

[jkall]

We need to do a complete review of logger data (and metadata) management in db.

https://github.com/jkall/qgis-midvatten-plugin/issues/205 https://github.com/jkall/qgis-midvatten-plugin/issues/57 https://github.com/jkall/qgis-midvatten-plugin/issues/50 (see "sanity check") https://github.com/jkall/qgis-midvatten-plugin/issues/44 https://github.com/jkall/qgis-midvatten-plugin/issues/43

The main issue is: https://github.com/jkall/qgis-midvatten-plugin/issues/83