fix: CLI Performs Changes to User System

[ofekd]

App ID: N/A

Description

The CLI seems to be making environment changes on the user system which I consider to be an overreach. The two main issues I bumped into are:

(1) Managing the flutter and dart installations (2) Attempting to access .zshrc

I can imagine why (1) may be necessary, although it'll be much preferable to be able to opt out of it. I'd rather keep control of the versions myself.

The .zshrc access is completely unacceptable. I'm not sure if it's Shoebird doing it or a binary/script Shoebird calls, but even runninng shoebird help result in an attempt to access .zshrc:

$ ../shorebird/bin/shorebird help                                                                                       
PathAccessException: Cannot open file, path = '/home/<user>/.zshrc' (OS Error: Permission denied, errno = 13)
The shorebird command-line tool

Usage: shorebird <command> [arguments]

Global options:
-h, --help            Print this usage information.
    --version         Print the current version.
-v, --[no-]verbose    Noisy logging, including all shell commands executed.

Available commands:
  cache      Manage the Shorebird cache.
  doctor     Show information about the installed tooling.
  flutter    Manage your Shorebird Flutter installation.
  init       Initialize Shorebird.
  login      Login as a new Shorebird user.
  login:ci   Login as a CI user.
  logout     Logout of the current Shorebird user
  patch      Manage patches for a specific release in Shorebird.
  preview    Preview a specific release on a device.
  release    Manage your Shorebird app releases.
  upgrade    Upgrade your copy of Shorebird.

Run "shorebird help <command>" for more information about a command.

Expected Behavior

Any side effects performed by a tool such as shoebird should be contained to the project directory.