proxy: support setting proxy via --proxyServer, PROXY_SERVER env var or PROXY_HOST + PROXY_PORT env vars (#589)

fixes #587 

The proxy env vars PROXY_HOST and PROXY_PORT were being ignored, as they
were hardcoded to obsolete values in the Dockerfile.

Proxy settings can now be set, in order of precedence via:
- --proxyServer cli flag
- PROXY_SERVER env var
- PROXY_HOST and PROXY_PORT env vars, which set an HTTP proxy server
only (for backwards compatibility with 0.12.x)

The --proxyServer / PROXY_SERVER settings are passed to the browser via
the --proxy-server flag.
AsyncFetcher / direct fetch also supports HTTP and SOCKS5 proxying.
Supported proxies are: HTTP no auth, SOCKS5 no auth, SOCKS5 with auth
(supported in Brave, but not Chrome!)

---------
Co-authored-by: Vinzenz Sinapius <Vinzenz.Sinapius@gmail.com>
Co-authored-by: Tessa Walsh <tessa@bitarchivist.net>

src/create-login-profile.ts

@@ -99,9 +99,10 @@ function cliOpts(): { [key: string]: Options } {
       default: getDefaultWindowSize(),
     },
 
-    proxy: {
-      type: "boolean",
-      default: false,
+    proxyServer: {
+      describe:
+        "if set, will use specified proxy server. Takes precedence over any env var proxy settings",
+      type: "string",
     },
 
     cookieDays: {
@@ -179,7 +180,7 @@ async function main() {
     headless: params.headless,
     signals: false,
     chromeOptions: {
-      proxy: false,
+      proxy: params.proxyServer,
       extraArgs: [
         "--window-position=0,0",
         `--window-size=${params.windowSize}`,