Replace pkger with go:embed for bundling the admin. Closes #844 (#1464)

* Replace pkger with go:embed for bundling the admin. Closes #844

* Remove references to pkged.go

* Point tests to use an updated version of Go

* Add comment to new exported function

* Cleanup

* Add a dummy pkged.go to alert people to stop using it.

* Add simple browser test to make sure the admin is available and renders

* Don't panic

.github/workflows/automated-browser.yml

@@ -5,6 +5,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          stable: 'false'
+          go-version: '1.17.2'
+
       - name: Run browser tests
         run: cd test/automated/browser && ./run.sh