[server] Add additional problem sources

[michaelfromyeg]

Find other sources on the interwebs with coding problems and add them. Maybe more from the Reddit API?

Don't really want to do any webscraping and break any TOS :/

Could also use VS Code web view and display the URL in a new tab IFF there is no text. Create a MD file with just the link instead. (This seems like a good way to go for Leetcode support.)