Appengine doesn't provide search API

[nanjarapalli]

Problem
There is no app engine API to search for device content in Astarte.
Only timestamp is considered in exiting API.
Due to the missing search API client side has to do the heavy lifting to fulfill the use cases.
This causes other problems that cannot be solved on the client side.
Look here for more details on the client-side issue.

Use cases

• Search a device exists or not in Astarte
• Search for specific param value match in the interface
• Filter the devices based on the connection status
• Filter the devices based on data volume size on a specific interface
• Filter the devices based on specific interface version
• and many more

Please consider the request and provide the search API as soon as possible.
Thanks in advance