UPDATE for RFC30: Serialization and deserialization (#2186)

* commit RFC

* commit

* Delete rfc0023_serialization_and_deserialization.md

* fix formatting

* https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1054637168

* https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1054632202

* applied grammarly
pre-commit

* better example wip

* FIX

* https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1054632468

https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1054818444

https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1054820192

* add examples for output's builer

* fixes

* fixing unstable feature gate snippet

* Update rfc0028_serialization_and_deserialization.md

Section is deleted in response to the discussion
https://github.com/awslabs/smithy-rs/pull/1944#discussion_r1061577656

* file name fix

* Update rfc0030_serialization_and_deserialization.md

https://github.com/awslabs/smithy-rs/pull/2183#discussion_r1064573442

* Update rfc0030_serialization_and_deserialization.md