[services] Tunnelbroker - Adding of the client authentication by the sessionID from metadata

Summary:
This diff introduces using of the metadata to provide the sessionID by the client for the client authentication in the gRPC MessagesStream bidirectional stream.

We are making the following security checks with the sessionID:

• Check if the sessionID is provided in metadata;
• Check the sessionID format validity;
• Check if the sessionID exists in the database session table.

Linear task: ENG-1359

Test Plan:

• Opening a MessagesStream from the gRPC client without providing the sessionID in metadata results in gRPC invalid argument error.
• Opening a MessagesStream from the gRPC client providing the sessionID in a wrong format in metadata results in gRPC unauthenticated error.
• Opening a MessagesStream from the gRPC client providing the unexistent sessionID in metadata results in gRPC unauthenticated error.

Reviewers: jon, marcin, tomek

Reviewed By: jon, tomek

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5528