Set up demo version for deployment

[sharmaadvay0]

• Disable register functionality
• Add alert on the register page saying that register won't work
• change "email address" to "username"
• remove username and password rules
• Delete course plans upon logout and opening app
• Set up so it deletes course plans on page close in the dashboard and plans page
• Add alert on the dashboard saying that plans won't save
• Set up so it deletes course plans after 30 mins if the user leaves the page open
• Remove where it saves token in local storage
• Change MongoURI and jwt and add it to gitignore
• perform other deployment changes in the code
• Set up a default demo user