Service filtering and retrieval improvements

[trema96]

Changes to getServices

• More efficient implementation of get services that uses map/reduce views only instead of requiring additional filtering on kraken
• Use contact modified date instead of service modified date to decide latest version.
• Should generally match, but in case of changes to contact level metadata, the service could remain unchanged.

Changes to service filtering

Previous implementation of service filtering would return all service ids that matched the request at some point. The new implementation will check that the latest version of the service still matches the request before returning it.

[trema96]

Partially included as part of #222, where the newly introduced filters use a reduced view for getting the contact with the latest version of a service:

• The actual "getServices" method was not yet updated
• Existing filters were unchanged

To complete this PR we need to:

• Add a new version of all existing filters that rely on the reduced view
  • They should probably allow to specify the VersionFiltering parameter like in Latest health element filters #264
• Ensure that either all DBs have indexed the view needed for this version of getServices, or have a fallback in case the view does not exist.