Overhaul errors in rust-runtime crates

[jdisanti]

• Add DisplayErrorContext to all tracing error logs
• Hide error source type in Unhandled variant in code generated errors
• Remove Clone from ProfileParseError and any others that have it
• Errors in rust-runtime
  • aws-smithy-async
    • crate::future::TimedOutError
  • aws-smithy-checksums
    • crate::body::Error
  • aws-smithy-client
    • crate::hyper_ext::HttpTimeoutError
    • crate::timeout::RequestTimeoutError
  • aws-smithy-eventstream
    • crate::error::Error
  • aws-smithy-http
    • crate::byte_stream::Error
    • crate::endpoint::Error
    • crate::endpoint::InvalidEndpoint
    • crate::header::ParseError
    • crate::operation::BuildError
    • crate::operation::SerializationError
    • crate::result::ConnectorError
    • crate::result::SdkError
    • crate::event_stream::receiver::Error
    • crate::event_stream::sender::MessageStreamError
  • aws-smithy-json
    • crate::escape::EscapeError
    • crate::deserialize::Error
  • aws-smithy-types
    • crate::base64::DecodeError
    • crate::error::Error
    • crate::TryFromNumberError
    • crate::primitive::PrimitiveParseError
    • crate::retry::RetryModeParseErr
    • crate::retry::RetryConfigErr
    • crate::timeout::error::ConfigError
    • crate::date_time::format::DateTimeParseError
    • crate::date_time::format::DateTimeFormatError
    • crate::date_time::ConversionError
  • aws-smithy-types-convert
    • crate::date_time::Error
  • aws-smithy-xml
    • crate::decode::XmlError
    • crate::encode::Error
  • inlineable
    • crate::endpoint_lib::InvalidArn
• Errors in aws-runtime
  • aws-types
    • crate::app_name::InvalidAppName
    • crate::credentials::CredentialsError
  • aws-endpoint
    • crate::AwsEndpointStageError
  • aws-http
    • crate::auth::CredentialsStageError
    • crate::content_encoding::AwsChunkedBodyError
    • crate::retry::UnmodeledError
    • crate::user_agent::InvalidMetadataVAlue
    • crate::user_agent::UserAgentStageError
  • aws-sigv4
    • crate::date_time::ParseError
    • crate::BuildError
  • aws-sig-auth
    • crate::middleware::SigningStageError
  • aws-inlineable
    • crate::http_body_checksum::Error
    • crate::presigning::Error
  • aws-config
    • crate::ecs::EcsConfigurationErr
    • crate::ecs::InvalidFullUriError
    • crate::json_credentials::InvalidJsonCredentials
    • crate::retry::RetryConfigError
    • crate::sso::LoadTokenError
    • crate::imds::InnerImdsError
    • crate::imds::InvalidEndpointMode
    • crate::imds::BuildError
    • crate::imds::TokenError
    • crate::profile::parser::ProfileParseError
    • crate::imds::ImdsError
• Stop using Box<dyn Error> as the top level error in aws-sigv4
• Examine making SdkError easier to use
• Re-export DisplayErrorContext in generated crates and reference from Unhandled doc comment
• Update RFC changes checklist and status
• Write upgrade guide

[jdisanti]

Examples fixed: awsdocs/aws-doc-sdk-examples#3967