Deprecations removal list

[jdisanti]

Types/functions that were deprecated in previous releases were removed. Unfortunately, some of these deprecations
were ignored by the Rust compiler (we found out later that #[deprecated] on pub use doesn't work), so those ones
are listed out below:

• AuthSchemeOptionResolver renamed to ResolveAuthSchemeOptions
• aws_smithy_types::Error moved/renamed to aws_smithy_types::error::Error
• aws_smithy_types::unhandled::Unhandled was removed with no replacement, but it shouldn't be needed
• EndpointResolver renamed to ResolveEndpoint
• IdentityResolver renamed to ResolveIdentity
• Interceptor renamed to Intercept
• RequestSerializer renamed to SerializeRequest
• ResponseDeserializer renamed to DeserializeResponse
• ResponseDeserializer renamed to DeserializeResponse
• Signer renamed to Sign