Feature: Fine-grained Timeout Configuration (#831)

* add: TimeoutConfig
add: provider to fetch timeout from profile
add: provider to fetch timeout from environment
add: default provider for TimeoutConfigs
update: aws_config::Config to support timeout conf
update: rustdoc lint

* add: TimeoutConfigBuilder::merge_with test

* update: changelogs

* add: timeout_config to client and builder
add: generic timeout service
add: non-working timeout layer

* add: timeout layer/service with configurable duration
add: test that ensures timeout service works

* fix: eliminate useless clones

* feature: Kotlin decorator for TimeoutConfig
add: tests for timeout-related codegen
update: incorrect package path in RetryConfigDecorator.kt
fix: outdated aws-config timeout config code

* remove: link to struct in external crate
fix: outdated doc test
fix: add missing import to doc test
fix: copypaste error in doc test
update: outdated lint name

* update: comment on Builder::timeout_config panics
add: test ensuring timeouts can't be infinite
update: use a floating point number in a timeout doc
update: message for failed profile load to mention that profile will be skipped
remove: commented out code
update: attempt to make difference between api_call_timeout and api_call_attempt_timeout clearer
update: outdated doc comments
update: TimeoutConfigError descriptions

* formatting: arrange imports in aws_smithy_client lib.rs
add: todo for improving timeout error categorization

* update: var parsers to work without needless allocations
update: improve example for default timeout config provider
update: improve example for default retry config provider
fix: unhelpful doc comment for TimeoutLayerFuture<T>
remove: outdated TODO

* fix: various typos in docs
add: PR links to changelogs
format: doc references to structs to look nicer
add: note about expected form and unit of timeout config data
update: expand ProfileFileTimeoutConfigProvider example

* fix: relocate provider config tests to the correct package/directory
remove: unimplemented timeouts from `Settings`

* add: S3 integration test for timeouts
update: re-enable TimeoutLayers
add: "list_of_set_timeouts" logging helper to TimeoutConfig
refactor: the way TimeoutService handles futures so that it can work better with no timeout set
add: helper structs to make creating timeout services easier

* update: split timeout_config example into multiple lines

* fix: Clippy lints

* fix: outdated test

* fix: more clippy lints

* fix: typo
add: TimeoutConfig example

* Update CHANGELOG.md

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* Update aws/rust-runtime/aws-config/src/default_provider.rs

Co-authored-by: Russell Cohen <rcoh@amazon.com>

* feature: user-configurable AsyncSleep impls
update: fallback to sleep impl that sleeps forever instead of sleep impl being optional

* Update rust-runtime/aws-smithy-types/src/timeout.rs

Co-authored-by: John DiSanti <jdisanti@amazon.com>

* update: changelogs
format: SleepImplDecorator.kt
update: TimeoutConfig doc
remove: list_of_set_timeouts in favor of Debug impl for TimeoutConfig

* Apply suggestions from code review

Co-authored-by: John DiSanti <jdisanti@amazon.com>

* fix: broken macro doc test by ignoring it
fix: outdated struct ref in doc
fix: outdated generated doc

* fix: mode broken doc tests

* fix: broken doc test

* attempt to fix CI-only doc test error

* add: moduleUseName method to CodegenContext
remove: pub use reexports from timeout and sleep impl decorators
add: pub use reexports to aws_config for timeout and retry configs
undo: default_sleep_impl changes
attempt to add tokio time feature to S3 integration test

* Update timeout.rs

* Apply suggestions from code review

Co-authored-by: John DiSanti <jdisanti@amazon.com>

* refactor: consolidate timeout parsing logic
rename: `RetryConfigBuilder::merge_with` to `RetryConfigBuilder::take_unset_from`
refactor: move timeout parsing tests to timeouts.rs
add: entry to SDK changelog noting the renaming
remove: redundant feature from s3 integration test Cargo.toml
update: various setters added by this PR to have the same form as our preexisting setters
add: extra info to the warning emitted when ConfigLoader calls default_async_sleep and gets None

* fix: tests broken when implementing suggestions

* update: doc hide sleep_impl for aws_types::Config
remove: leftover comment

Co-authored-by: Russell Cohen <rcoh@amazon.com>
Co-authored-by: John DiSanti <jdisanti@amazon.com>