Remove OperationRegistryBuilder and Router

[hlbarber]

The conclusion of Service Builder Improvements is the removal of the original service builder, OperationRegistryBuilder, along with it's output, Router.

A list of chores which should be done during the removal:

• Remove all Router associated code, and promote the protocol specific routers code to a more accessible module.
• Remove existing from_request/into_response methods #1706, this can be done prior to the removal and blocks the further steps.
• Remove rust-runtime/inlineable/src/server_operation_handler_trait.rs.
• Cleanup kotlin/software/amazon/smithy/rust/codegen/server/smithy/generators/ServerServiceGenerator.kt and integrate it with kotlin/software/amazon/smithy/rust/codegen/server/smithy/generators/ServerServiceGeneratorV2.kt.
• Remove kotlin/software/amazon/smithy/rust/codegen/server/smithy/generators/ServerOperationHandlerGenerator.kt.