* Support import/export for doc type history cleanup policy
* Support unset/null history cleanup value
* Resolve issue when api endpoints called without cleanup policy.
noop isn't good enough as map fails for response.
* null conditional vs null coalesce assignment
* Don't overwrite existing policy if omitted in import XML
* Update history cleanup warning and translations
* Change history cleanup alert to infomational styling
* Remove margin around history cleanup config
Co-authored-by: Ronald Barendse <ronald@barend.se>
13a51d3267