[identity] Implement RPC to log out secondary device

Summary:
Implementation of the RPC described in D12119. Details and linked issues there.
This RPC needs to:

• Verify if the device is on the device list
• Clear device CSAT
• Clear device data (prekeys etc)
• Clear OTKs

Depends on D12119

Test Plan:

• Registered a user (Identity-auto created device list with primary device).
• Logged in with a second device (secondary device added to the list)
• Called the RPC on the secondary device
  • Confirmed that CSAT as well as device keys were cleared by viewing DDB tables
  • Confirmed that the device ID still exists on the device list

Also confirmed that the RPC fails:

• If the device is not on the device list
• If the device is a primary device

Reviewers: varun, will, kamil

Reviewed By: kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D12120