Add HTTP GET queries proxying

[modship]

• [ ] document all added functions
• [ ] try in sandbox /simulation/labnet
• [ ] unit tests on the added/changed features
  • [ ] make tests compile
  • [ ] make tests pass
• [ ] add logs allowing easy debugging in case the changes caused problems
• [ ] if the API has changed, update the API specification

closes #3376

Supported resources are:

• [x] addresses
• [x] blocks
• [x] endorsements
• [x] operations