High return-on-investment features

[peter1357908]

• introduction in login and signup page; link to this repo, API documentation, and peterish.com notes.
• Allowing deleting account
• responsive hamburger top bar menu (for mobile). Reference: https://javascript.works-hub.com/learn/how-to-create-a-responsive-navbar-using-material-ui-and-react-router-f9a01
• make a popup suggesting to go landscape on mobile (and make signup & login better in landscape)
• make plate draggable on mobile (turned out to be an issue with react-draggable)
• add loading indication (will be useful if we migrate back to servers that need to take 30s to wake up after inactivity...)
• save plate(s) to file, and load plate(s) from file
• "do not prompt again" (e.g., plate deletion).
• "save and continue with current action" in confirm dialogs
• Highlight modified wells (and plateName)