Filters: Make label configurable from outside

[pehbehbeh]

Idea from @krns:

To increase the reusability, a label should be configurable from the outside. The following filter can only be used when the label is the same:

defmodule EvuPlatformWeb.Filters.DateRange do
  @moduledoc false

  use Backpex.Filters.Range
  import EvuPlatformWeb.Gettext

  @impl Backpex.Filters.Range
  def type, do: :datetime

  @impl Backpex.Filter
  def label, do: dgettext("time_tracking", "Date")
end

[pehbehbeh]

This should be covered by #336 and #357.

[Flo0807]

Solved with #226 @pehbehbeh