config: add commit ID

Primary impetus is to determine whether the reported TUS errors are due to old code, but the commit ID can be re-used in other areas where it makes sense.

The value comes externally from the command line, e.g.:
  `COMMIT_ID=$(git rev-parse HEAD) NODE_ENV=development yarn dev:web`

config.js

@@ -93,6 +93,10 @@ const config = {
 
   AD_KEYWORD_BLOCKLIST: process.env.AD_KEYWORD_BLOCKLIST,
   AD_KEYWORD_BLOCKLIST_CHECK_DESCRIPTION: process.env.AD_KEYWORD_BLOCKLIST_CHECK_DESCRIPTION,
+
+  // FROM COMMAND LINE
+  COMMIT_ID: process.env.COMMIT_ID,
+  NODE_ENV: process.env.NODE_ENV,
 };
 
 config.SDK_API_PATH = `${config.LBRY_WEB_API}/api/v1`;