Added router to rediect github auth

[bisht-richa]

Summary

Fixes #9138

Fixed issue - Unable to use Auth Providers when running locally

To test

setup github auth provider

[nwmac]

This used to work pre-Nuxt removal - this was handled by shell/server/server-middleware.js.

This was removed when we removed Nuxt - although the server-middleware.js file is still in the codebase. It looks like serverMiddleware in shell/vue.config.js is never used - it did not get wired into vue.config (where as it was wired into nuxt.config).

We should be able to wire serverMiddleware back into vue.config via setupMiddlewares on devServer - see: https://cli.vuejs.org/config/#devserver and https://webpack.js.org/configuration/dev-server/#devserversetupmiddlewares

NOTE: This needs to be wired in ONLY when running in dev locally - which the above would do - the current code in this PR wires this in, in all cases.

@richard-cox ^^^

[richard-cox]

This hasn't covered part of the request from #9138 (comment)

• the process to add server middleware via the old serverMiddleware array is still in shell/vue.config.js. At the very least serverMiddleware.push(path.resolve(dir, SHELL, 'server', 'server-middleware')); should be removed
• there's no clear way forward to address that now defunct old method using the serverMiddleware array (specifically the other parts that don't work in post nuxt world). Can you create an issue to cover them?

[bisht-richa]

• there's no clear way forward to address that now defunct old method using the serverMiddleware array (specifically the other parts that don't work in post nuxt world).

I have removed unused code and created an issue for serverMiddleware array : #9312