Refactor origin_ui to web_ui to reuse basic logic for server web UI/API

[haoming29]

Closes #308

• This PR also introduced basic username/password auth and its set of APIs to all servers, as well as common APIs such as /config, /health to all servers
• Changed the auth URLs from /api/v1.0/origin_ui to /api/v1.0/auth/, the origin UI code is updated to the correct URLs
• Changed the name for one-time activation code and web ui password file to server-web-activation-code and server-web-passwd respectively.
• Put /health API behind the authentication middleware

Testing Instructions

• Spin up your director registry and origin
• Go to https://localhost:8444/view and ensure you can visit origin's web ui as before
• Close all servers and remove origin-ui-passwd under your /etc/pelican directory
• Restart any of the server and you should be able to see that the terminal shows the one-time passcode to initialize the UI, although you can only do it through origin UI now.
• Go to the terminal where origin runs, find the one-time code and go to the origin's initialization page, activate UI using the code, and set your new admin password.
• Under your /etc/pelican now you should see a server-web-passwd

[turetske]

I have some questions about how some of the files will work if we have multiple web-ui's enabled, which will definitely be possible in the future and I don't want us backed into a corner now.

[turetske]

LGTM!