First attempt at automated Playwright tests (#402)

* First attempt at automated Playwright tests

* Fix deb installation in CI

* Try again with .deb

* Try xvfb

* Fix paths

* Prepare macOS runner for UI tests

* test_artifacts

* Increase test timeout to 30s

* Add timeout

* Split out build & test stages for easier retrying

* Use a single test matrix job

* Fix testing

* Yarn install

* Install deps

* Make prep more generic

* Update build.yaml

* Update build.yaml

* Update build.yaml

tsconfig.json

@@ -14,9 +14,11 @@
     "lib": [
       "es2019",
       "dom"
-    ]
+    ],
+    "types": ["jest", "node"],
   },
   "include": [
-    "./src/**/*.ts"
+    "./src/**/*.ts",
+    "./tests/**/*.ts"
   ]
 }