Custom property names must be used in SourceFilter and source fields

[sothawo]

When a property has a custom name defined with the @Field annotation, this is not considered/used when a query is created that has a SourceFilter or source fields set.

[sothawo]

backported to 4.2. can only backported to 4.1 or 4.0 with lots of adaptions - not doing this now as source filter and source fields are not used commonly and there always is the workaround to set the Elasticsearch names into the source filter and fields.