billing: Add date range and json/yaml output for billing search tool

Adds the --since and --until options to the billing search command.
Also adds JSON and YAML output options.

The JSON and YAML formats should not be expected to never change. We
may adjust the format in future versions.

Target: trunk
Require-notes: yes
Require-book: yes
Acked-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Patch: https://rb.dcache.org/r/7010/