Rollup of 4 pull requests (#610)

* Updated EBS code example docs (#587)

* Updated EBS code example docs; added delete-snapshot, get-snapshot-state, and list-snapshots code examples

* Updated EBS code examples based on feedback

* Updated EBS code examples to follow latest code guidelines and proper service naming

* Refactored Kinesis code examples (#549)

* Reordered crates in Cargo.toml; refactored code examples to use common example pattern

* Updated Kinesis code examples to use ? instead of expect()

* Updated Kinesis code examples based on feedback

* Refactored Lambda code examples (#552)

* Re-ordered crates in Cargo.toml; refactored Lambda code examples to use common example pattern; added change-java-runtime and list-all-functin-runtimes code examples

* Updated Lambda code examples to use ? instead of expect()

* Updated Lambda invoke-function code example to use InvokeErrorKind::ResourceNotFoundException

* Updated Lambda code examples to use latest pattern

* Refactored CognitoIdentity code examples (#584)

* Updated CognitoIdentity code examples to use -v (verbose) option; added describe-identity-pool and list-pool-identities

* Updated docs for Cognito identity pool code examples

* Updated CognitoIdentity list-pool-identies code example based on feedback

* Updated Cognito identity pool code examples based on feedback

Co-authored-by: Doug <dougsch@amazon.com>