Support OAuth for Jira api

[wwwlicious]

It would be great if the app supported OAuth for Jira. Details for implementing can be found @ https://developer.atlassian.com/cloud/jira/platform/jira-rest-api-oauth-authentication/

[MattMofDoom]

@aliozgur I was thinking to look at something like this at some stage. I'm not totally sure how OAuth 2.0 could be done for the Seq app scenario since it has some complexity that I can see in execution (it would require users to follow a documented set of steps correctly, given the Seq settings interface limitations).

As a first step, it should be viable to implement https://developer.atlassian.com/cloud/jira/platform/basic-auth-for-rest-apis/ which will work with Jira Cloud, while still supporting the username/password combination for Jira Server.