Manually input and automatically track US stocks

[crnsh]

Solves #131. WIP

• [x] UI for adding a manual investment account — Would use the existing "Investment" block in the modal, where you'd either pick an existing account or add a new one.
• [x] UI for adding the stock — Should be a "search to select" UI for pulling from stock listing (Database: Security)
• [ ] Creating the appropriate "transaction" for adding the stock.
• [ ] UI for removing/selling the stock
• [ ] Create the appropriate "transaction" for removing the stock.