This includes:
Create/update policy resource
Attachments support for policy resource (with support for writing the attachment to both s3 and fs repositories)
Opa policy type implementation, including compiling rego code to wasm and adding that to the policy as an attachment

implemented full flow with basic features
Implement local policy attachment caching for all resource repositories

#141)

* Add policy definitions and attachments to request context, change policy executor to use them from context instead of directly from repo

* PR comments

… args) (#144)

* change policy directive to accept only a single policy

* Refactored PolicyExecutor API to only expose static methods