Title: Registering a new Lokole client
Lokole client -> Lokole server: Register client domain via CreateClient action
Lokole server -> Github API: Authenticate requesting user
Lokole server --> Registration worker: Trigger RegisterClient action via Azure ServiceBus
Lokole server -> Lokole client: Return 201
Registration worker -> Registration worker: Assign unique client id
Registration worker -> Sendgrid API: Register inbound parse webhook for client id
Registration worker -> Cloudflare API: Set Sendgrid as the MX server for the client domain
Registration worker -> Azure Storage (auth container): Store client details and unique client id
Lokole client -> Lokole server: Poll for client domain details via GetClient action
Lokole server -> Azure Storage (auth container): Fetch client details and verify requesting user owns client domain
Lokole server -> Lokole client: Return 200 with client details and unique client id