Prompt installing for dependencies instead of exiting.

[gdotdesign]

This PR adds a prompt to install dependencies instead of displaying an error and exiting when dependencies are missing (mint build, mint test, mint start).

This is how the installing looks like:

Mint - Running the development server
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
⚙ Ensuring dependencies...
 ↳ Not all dependencies in your mint.json file are installed.
   Would you like to install them now? (Y/n)

⚙ Constructing dependency tree...
  ✔ Updated mint-color (https://github.com/mint-lang/mint-color.git)
  ✔ Updated mint-tabler-icons (https://github.com/mint-lang/mint-tabler-icons.git)

⚙ Resolving dependency tree...
  ◈ mint-color ➔ 0.7.0
  ◈ mint-tabler-icons ➔ 1.0.0

⚙ Copying packages...
⚙ Parsing files... 579.817ms
⚙ Development server started on http://127.0.0.1:3000/

This is how the not installing looks like:

Mint - Running the development server
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
⚙ Ensuring dependencies...
 ↳ Not all dependencies in your mint.json file are installed.
   Would you like to install them now? (Y/n)

⚠ Missing dependencies...
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
There was an error, exiting...

Fixes #664