This issue collates the work required to properly support hosting the Acropolis stack on GCP. For basic support (compute engine, GCS, PostgreSQL or MySQL database instances): * bbcarchdev/libawsclient#1 - Support AWSv4 authentication Extended support: * bbcarchdev/libsql#8 - Support for Google Spanner * bbcarchdev/libmq#6 - Support Google PubSub as an MQ source Tracked internally as [RESDATA-1266](https://jira.dev.bbc.co.uk/projects/RESDATA/issues/RESDATA-1266)