* Add Read methods for KVClient
* KV write helper
* Add changelog
* Add Delete method
* Use extractVersionMetadata inside extractDataAndVersionMetadata
* Return nil, nil for v1 writes
* Add test for extracting version metadata
* Split kv client into v1 and v2-specific clients
* Add ability to set options on Put
* Add test for KV helpers
* Add custom metadata to top level and allow for getting versions as sorted slice
* Update tests
* Separate KV v1 and v2 into different files
* Add test for GetVersionsAsList, rename Metadata key to VersionMetadata for clarity
* Move structs and godoc comments to more appropriate files
* Add more tests for extract methods
* Rework custom metadata helper to be more consistent with other helpers
* Remove KVSecret from custom metadata test now that we don't append to it as part of helper method
* Return early for readability and make test value name less confusing
