Added support for streaming response modification

[usrivastava92]

Description

This issue has been open for almost 3 years now, multiple PRs have been raised and been rejected / closed. This PR another attempt to fix this issue. Spring cloud gateway ModifyResponse filter blocks the calls in case of streaming responses.

• https://github.com/spring-cloud/spring-cloud-gateway/issues/2775
• https://github.com/spring-cloud/spring-cloud-gateway/issues/2275

Fixes gh-2275

FIx

• The fix introduces separate rewrite function to for modification of streaming and non streaming responses.
• To keep the changes backwards compatible the old rewrite function has not been removed and has been marked as deprecated

[usrivastava92]

Hi @spencergibb please review the PR and let me know your thoughts on this.