test(tree-details-summary): add unit tests

- Simple test to check if the endpoint returns the expected
  structure
- Test filter for tests/boots status
- Test filter for builds status
- Test filter for configs
- Test filter for architectures
- Test filter for compilers
- Test filter for hardware
- Test filter for issues
- Test filter for invalid filter values
- Added `--run-all` flag to pytest to be able to skip some tests during
  pre-push

Closes #985

backend/conftest.py

@@ -0,0 +1,4 @@
+def pytest_addoption(parser):
+    parser.addoption(
+        "--run-all", action="store_true", default=False, help="run all test cases"
+    )