🐛 Fix task filtering and sorting.

[jortel]

Fix issues reported here.

1. sorting seems to work only for id field i.e.
2. filtering not supported for createUser and id fields( both listed in the enhancement)
3. application name is missing in the response and in filtering. Filtering by application ID works but this is not so nice.
4. priority is missing in the response and in the filtering
5. for kind the filtering is supported by the server but it seems it's not included in the response

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Filter and sorting: needed to support GORM join queries which qualifies fields by table.

Example: For a task query joined with application, produces all of the task fields qualified as table.column:

SELECT task.id, task.name ...

And the (joined) application fields prefixed with APPLICATION__

SELECT APPLICATION__ID, APPLICATION__NAME ...

[jortel]

hint: Support field names with (.) that are not nested resources (in the filter).

[mansam]

LGTM