User-defined app execution aliases

Currently, packaged apps can declare an app execution alias for the process, which enables them to be launched from the command line as it was in the Path environment variable.

I think this is a much superior model because:

• The user can turn on or off which ones they want
• It doesn't need to be in a particular folder that's in the Path environment variable
• The actual executable name doesn't need to match the app execution alias

However, it is not possible to define an app execution alias for any executable yourself. Most utilities don't come packaged so this is really a significant limitation. Basically, provide a box in the "app execution aliases" settings page where you can type the alias and the executable location and it's possible to type the alias in a terminal to launch the program, without even adding the folder in which its located to the Path environment variable.

No files or tests are named. Start by examining the existing app execution aliases settings page and how packaged aliases are exposed to a terminal; define the user-facing behavior for entering an alias and executable location, including enabling or disabling it and launching without modifying PATH.