clients: add cbc proxy clients

We are going to invoke a lambda to send a message to the CBC

We need a CBC Proxy Client to do this

The Client will be able to send/update/cancel broadcasts in the CBC

Unless we have configured the app with AWS credentials for the
CBCProxyClient, we just want to use a client that does nothing: the noop
client

The AWS access keys are separate for the CBC Proxy vs other Notify AWS
things because the CBC Proxy lives in another AWS account

Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
Co-authored-by: Katie <katie.smith@digital.cabinet-office.gov.uk>

app/clients/cbc_proxy.py

@@ -0,0 +1,59 @@
+# Noop = no operation
+class CBCProxyNoopClient:
+
+    def init_app(self, app):
+        pass
+
+    def create_and_send_broadcast(
+        self,
+        identifier, headline, description,
+    ):
+        # identifier=broadcast_message.identifier,
+        # headline="GOV.UK Notify Broadcast",
+        # description=broadcast_message.description,
+        pass
+
+    # We have not implementated updating a broadcast
+    def update_and_send_broadcast(
+        self,
+        identifier, references, headline, description,
+    ):
+        pass
+
+    # We have not implemented cancelling a broadcast
+    def cancel_broadcast(
+        self,
+        identifier, references, headline, description,
+    ):
+        pass
+
+
+class CBCProxyClient:
+
+    def init_app(self, app):
+        self.aws_access_key_id = app.config['CBC_PROXY_AWS_ACCESS_KEY_ID']
+        self.aws_secret_access_key = app.config['CBC_PROXY_AWS_SECRET_ACCESS_KEY']
+        self.aws_region = 'eu-west-2'
+
+    def create_and_send_broadcast(
+        self,
+        identifier, headline, description,
+    ):
+        # identifier=broadcast_message.identifier,
+        # headline="GOV.UK Notify Broadcast",
+        # description=broadcast_message.description,
+        pass
+
+    # We have not implementated updating a broadcast
+    def update_and_send_broadcast(
+        self,
+        identifier, references, headline, description,
+    ):
+        pass
+
+    # We have not implemented cancelling a broadcast
+    def cancel_broadcast(
+        self,
+        identifier, references, headline, description,
+    ):
+        pass