Move all tests to single directory "tests"

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>

tests/integration/extends_w_file_subdir/docker-compose.yml

@@ -0,0 +1,8 @@
+version: "3"
+services:
+  web:
+    extends:
+      file: sub/docker-compose.yml
+      service: webapp
+    environment:
+      - DEBUG=1

tests/integration/extends_w_file_subdir/sub/docker-compose.yml

@@ -0,0 +1,12 @@
+version: "3"
+services:
+  webapp:
+    build:
+      context: docker/example
+      dockerfile: Dockerfile
+    image: localhost/subdir_test:me
+    ports:
+      - "8000:8000"
+    volumes:
+      - "/data"
+

tests/integration/extends_w_file_subdir/sub/docker/example/Dockerfile

@@ -0,0 +1 @@
+FROM nopush/podman-compose-test as base