Integrate with iitkgp-erp-login properly

[proffapt]

• The file of interest is network.py and hence gyft.py

Network.py has various things which are already handled by the package itself, like:

• Specifying cookies separately anywhere (this is handled well enough internally)
• No need to "refresh_cookies" - not sure, test this claim

Thus the functions of interest are:

• refresh_cookies -> Not needed
• post -> Remove usage of cookies
• login -> Update accordingly

[proffapt]

Won't be needed as session manager is in progress.