Deprecate setContentDecoderRegistry to populate contentDecoder

[arturobernalg]

Adapt InputStreamFactory map into contentDecoder via DecompressingEntity adapters

[ok2c]

@arturobernalg I spotted another problem. The LinkedHashMap<ContentCoding, UnaryOperator<HttpEntity>> map used by HttpClientBuilder basically means one cannot plug-in 3rd party coders if they are not in present in ContentCoding. This is not good. The map should be LinkedHashMap<String, UnaryOperator<HttpEntity>>. This needs to be corrected first.

[arturobernalg]

@arturobernalg I spotted another problem. The LinkedHashMap<ContentCoding, UnaryOperator<HttpEntity>> map used by HttpClientBuilder basically means one cannot plug-in 3rd party coders if they are not in present in ContentCoding. This is not good. The map should be LinkedHashMap<String, UnaryOperator<HttpEntity>>. This needs to be corrected first.

@ok2c I just made the change

[ok2c]

@arturobernalg I would like to propose an alternative approach. Could you live with #678?

[ok2c]

Superseded by #678