* Added new Config for SidecarService in ServiceDefinitions.
* WIP: all the code needed for SidecarService is written... none of it is tested other than config :). Need API updates too.
* Test coverage for the new sidecarServiceFromNodeService method.
* Test API registratrion with SidecarService
* Recursive Key Translation 🤦
* Add tests for nested sidecar defintion arrays to ensure they are translated correctly
* Use dedicated internal state rather than Service Meta for tracking sidecars for deregistration.
Add tests for deregistration.
* API struct for agent register. No other endpoint should be affected yet.
* Additional test cases to cover updates to API registrations
* doc: document discrepancy between id and CheckID
* doc: document enable_tag_override change
* config: add TranslateKeys helper
TranslateKeys makes it easier to map between different representations
of internal structures. It allows to recursively map alias keys to
canonical keys in structured maps.
* config: use TranslateKeys for config file
This also adds support for 'enabletagoverride' and removes
the need for a separate CheckID alias field.
* config: remove dead code
* agent: use TranslateKeys for FixupCheckType
* agent: translate enable_tag_override during service registration
* doc: add '.hcl' as valid extension
* config: map ScriptArgs to args
* config: add comment for TranslateKeys
