Support global-agent for central proxy configuration (#3423)

* * Added global-agent as central Global HTTP/HTTPS proxy configurable using environment variable
**  https://www.npmjs.com/package/global-agent
* Server-Bootstrap on index.js
** import 'global-agent/bootstrap'
* added dep in package.json
** global-agent: "^3.0.0

* * Added global-agent as central Global HTTP/HTTPS proxy configurable using environment variable
**  Added env variables

* update env example

* update env and lock file

* update env and lock file

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Co-authored-by: Henry <hzj94@hotmail.com>

packages/server/src/index.ts

@@ -22,6 +22,7 @@ import flowiseApiV1Router from './routes'
 import errorHandlerMiddleware from './middlewares/errors'
 import { SSEStreamer } from './utils/SSEStreamer'
 import { validateAPIKey } from './utils/validateKey'
+import 'global-agent/bootstrap'
 
 declare global {
     namespace Express {