Content-Length, chunked transfer encoding and Host header improvements

[vigoo]

Some fixes and improvements based on recent Discord discussions:

• If there is already a Host header set, it is not going to be overwritten based on the request url
• Content length information is now attached to the various Body types. If the content length is set, we will not use chunked transfer encoding, regardless of the body is streaming or not.
• Some Body and Handler constructors are duplicated now having a variant that gets a known content length, and one that does not (using the post-fix Chunked for them)

[codecov-commenter]

Codecov Report

Attention: 29 lines in your changes are missing coverage. Please review.

Comparison is base (c846a86) 64.47% compared to head (a694478) 64.37%.

Files	Patch %	Lines
...rc/main/scala/zio/http/netty/NettyBodyWriter.scala	41.66%	14 Missing ⚠️
zio-http/src/main/scala/zio/http/Body.scala	60.00%	4 Missing ⚠️
zio-http/src/main/scala/zio/http/Handler.scala	0.00%	4 Missing ⚠️
...main/scala/zio/http/codec/internal/BodyCodec.scala	0.00%	2 Missing ⚠️
...scala/zio/http/codec/internal/EncoderDecoder.scala	33.33%	2 Missing ⚠️
...http/src/main/scala/zio/http/netty/NettyBody.scala	60.00%	2 Missing ⚠️
zio-http/src/main/scala/zio/http/Response.scala	0.00%	1 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2563      +/-   ##
==========================================
- Coverage   64.47%   64.37%   -0.11%     
==========================================
  Files         140      140              
  Lines        8302     8333      +31     
  Branches     1496     1503       +7     
==========================================
+ Hits         5353     5364      +11     
- Misses       2949     2969      +20     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.