Deprecate QueryMap.encode, remove processing of the "encode" parameter

[vitalijr2]

Was mentioned in #1475:

• as Param.encode is deprecated,
• as we have two encode steps:
  • first processes encode parameter in ReflectiveFeign
  • but second ignores[1][2] it when build a query string in CollectionFormat.join, especially for names (fields),
• as UriUtils.encode does not encode string if it is already encoded.

I propose:

• encode both names and values in ReflectiveFeign, leave another names' encoding in CollectionFormat as it is not conflict with first. see UriUtils.isEncoded
• mark QueryMap.encode as deprecated too.