Move VUMI_INSTALLED_APPS and VUMI_INSTALLED_ROUTERS into go.config helper functions.
Remove old ways of accession conversation and router definitions from go.account, go.api.go_api and go.vumitools.
Add utility for patching config.
Use new config patching in tests.
Add helpers for accessing entire config.
Merge branch 'develop' into feature/issue-782-temporary-config-solution
Merge branch 'feature/issue-782-temporary-config-solution' into develop