add support for authenticated requests TO rdpc using app to app tokens

[rosibaj]

The aggregator connects to the rdpc-api, which now requires AUTH headers to allow for data extraction. We need to add support for authenticated requests to rdpc using app to app tokens. The aggregator needs to:

• send auth headers to rdpc-api on all calls for authorization

• be registered as an application in ego

• be able to generate an app token from ego that is sent in the headers

• register aggregator as a application in ego; store secrets in vault

• write some code/use a library to refresh the auth token regularly.

• hold onto the jwt in memory; use it normally;

• each time we try and reach out to rdpc-api, do a preflight check on duration of jwt as a self-validation before reaching out to jwt., if it has not expires use it, it it has not

• issue an application token and use it in the auth headers to the rdpc-gateway-api

[rosibaj]

@Buwujiu I need a version label on this ticket before we can release it.