Sync: update the directory structure convention for policies

Currently policies are created in a Git repo with the following structure, where group is a directory and policy name and version are separated with underscore _ symbol.

/group/policyname_1.0.rego

We need to update the structure so that each part is a separate directory and the final directory can contain multiple static files loaded during policy execution as data. The example above should be transformed to the following:

/group/policyname/1.0/policy.rego
/group/policyname/1.0/data.json

If there is data.json file inside the directory, it should be synced too as an attribute of the policy record in Mongo. For example, a synced policy in Mongo is a JSON object similar to:

{
  "name":"policyname",
  "group":"examplegroup",
  "version":"1.0",
  "locked":false,
  "data": {...}
}

The data field could be empty, but if such static data file is found in the directory, it should be placed in the data attribute of the policy.