Implement device flow

[Link-]

Currently only the server to server token creation flow has been implemented.

Another very useful token would be the OAuth access token more specifically the Device flow.

This issue is to implement the device flow.

Implemented	Token type	Prefix	More information
N.A	Personal access token	ghp_	"Creating a personal access token"
No	OAuth access token	gho_	"Authorizing OAuth Apps"
No	User-to-server token for a GitHub App	ghu_	"Identifying and authorizing users for GitHub Apps"
Yes	Server-to-server token for a GitHub App	ghs_	"Authenticating with GitHub Apps"
No	Refresh token for a GitHub App	ghr_	"Refreshing user-to-server access tokens"

cc: @jonico

[kingznqueenz]

Thank u