Fix UI Login

[cju8676]

Replace login overlay with more robust login page and authentication that restricts users from accessing pages if they are not logged in (perhaps using Spring Auth or something similar)

[cju8676]

Major acceptance criteria:

• Current login uses a "secure RNG" UserRepository line 177 and encodes to hex string (line 180) Change hex encoded RNG to more robust JWT token usage

• Endpoints that give secure information like CVE's / review / search, etc. should all require a header that validates a logged in user using their JWT token in the form "

• Restrict UI routing to secure pages if no token is stored

[cju8676]

(store the JWT token instead of current RNG hex token)