* Normalize event configuration
This updates event configuration stanzas to more closely match behavior
for listeners and kmses:
* Singular "sink" instead of "sinks" (probably not the most correct
option, but a consistent option, and one that makes sense for HCL)
* Allows sinks to have the type defined at the start of the block
* Moves type-specific configuration to a specific named block
Co-authored-by: Jim <jlambert@hashicorp.com>
Jeff MitchellandJim