Retrieve Connection Credentials from macOS Keychain

[SeanSith]

As a user, I would like to be able to utilize the functionality TablePlus implements in macOS Keychain for database credentials.

• In the Alfred list of connections, a hotkey combination will expose the connection's ID. This ID can be used to search in Keychain and the password shown from there.
• Alternatively, in the Alfred list of connections, a hotkey combination would result in a popup which would expose the credentials. This may result in dialogs from Keychain to enter passwords, so this needs to be carefully explained in documentation.