Custom fields plugin: Make custom fields search- and filterable (esp. in timesheet and invoicing)

[Sarmingsteiner]

It would be greatly appreciated if the custom fields created could be made searchable and filterable, especially in the timesheet section and ideally in the invoicing section as well.

[kevinpapst]

You can search for them: https://www.kimai.org/documentation/timesheet.html#filter-and-search