Run tests Docker in Docker (#261)

* Try running tests in Docker

* Spawn new container for each test

* Store test artifacts outside of mount

* When requested, build up to date image in test script

* sudo is unneccessary in containerized test env

* Skip azure test

* Backdate fixture file in JSON database

* Pin versions for azure tools

* Mount temp volume for /var/lib/docker to prevent dangling ones created by VOLUME instruction

* Fail backdating tests with message

* Add some documentation on test setup

* Cache images

* Run compose stacks with shortened default timeout

test/dropbox/docker-compose.yml

@@ -9,7 +9,7 @@ services:
     ports:
       - 8080:8080
     volumes:
-      - ./user_v2_ready.yaml:/etc/openapi/user_v2.yaml
+      - ${SPEC_FILE:-./user_v2.yaml}:/etc/openapi/user_v2.yaml
 
   oauth2_mock:
     image: ghcr.io/navikt/mock-oauth2-server:1.0.0