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>

test/utils/helpers.ts

@@ -3,6 +3,8 @@ import { promises as fs } from "fs"
 import * as net from "net"
 import * as os from "os"
 import * as path from "path"
+import { CodeServer, CodeServerPage } from "../e2e/models/CodeServer"
+import { REVERSE_PROXY_PORT, REVERSE_PROXY_BASE_PATH } from "./constants"
 
 /**
  * Spy on the logger and console and replace with mock implementations to
@@ -119,3 +121,18 @@ export function isAddressInfo(address: unknown): address is net.AddressInfo {
     (address as net.AddressInfo).address !== undefined
   )
 }
+
+/**
+ * If using a proxy, return the address of the proxy.
+ *
+ * Otherwise, return the direct address of code-server.
+ */
+export async function getMaybeProxiedCodeServer(codeServer: CodeServerPage | CodeServer): Promise<string> {
+  const address = await codeServer.address()
+  if (process.env.USE_PROXY === "1") {
+    const uri = new URL(address)
+    return `http://${uri.hostname}:${REVERSE_PROXY_PORT}/${uri.port}/${REVERSE_PROXY_BASE_PATH}/`
+  }
+
+  return address
+}