Allow to specify multiple `appID`s depending on role

[harnyk]

Problem

Currently, one account can only be associated with one appID. This seems to be an issue, because some configurations a specific appID per each role.

Solution

Allow to optionally specify multiple appIDs depending on role using a map field appIDsByRole in the account struct.

Example:

accounts:
  - name: ACME Dev
    appIDsByRole:
      admin: "123456"
      readonly: "987654"
    accountID: "111111111111"
    profileName: acme-dev

roles:
  - admin
  - readonly

Backwards compatibility

This is backwards compatible, because if appIDsByRole is not specified, the appID field is used.