feat(e2e): add support running behind proxy (#5348)

* docs: update maintaining

* chore(e2e): add maxFailures to playwright

* fix(ci): skip submodule in e2e job

We don't need the submodules for the e2e job. This will speed up the
checkout step.

* feat(ci): add test-e2e-proxy job

This adds a new job to CI to run our tests behind Caddy and simulate
code-server running against a reverse-proxy.

* refactor: make e2e work with reverse proxy

This refactors the e2e test in a couple ways:
- remove setting cookie in localStorage (instead we pass --auth none)
- refactor address() method to account for reverse proxy logic

* Update test/e2e/models/CodeServer.ts

* Update test/playwright.config.ts

* Update test/utils/constants.ts

Co-authored-by: Asher <ash@coder.com>

* Update test/utils/helpers.ts

Co-authored-by: Asher <ash@coder.com>

Co-authored-by: Asher <ash@coder.com>

ci/Caddyfile

@@ -0,0 +1,15 @@
+{
+	admin    localhost:4444
+}
+:8000 {
+	@portLocalhost path_regexp port ^/([0-9]+)\/ide
+        handle @portLocalhost {
+		uri strip_prefix {re.port.1}/ide
+                reverse_proxy localhost:{re.port.1}
+        }
+
+	handle {
+                respond "Bad hostname" 400
+        }
+
+}