Add option --dest-dir to config init, removed noop --save-as

[masci]

The option --save-as to the command config init is a no-op and has been removed.

A new option --dest-dir was added that can be used to specify a destination folder where to put the configuration file.

Fixes #570

[kittaakos]

I have verified it locally, and it works as expected. ✨

akos.kitta@Akoss-MacBook-Pro arduino-cli % pwd
/Users/akos.kitta/git/arduino-cli
akos.kitta@Akoss-MacBook-Pro arduino-cli % rm -rf ~/Library/Arduino15 && rm -rf ~/Documents/Arduino
akos.kitta@Akoss-MacBook-Pro arduino-cli % git rev-parse --short HEAD                              
5c21c083
akos.kitta@Akoss-MacBook-Pro arduino-cli % ./arduino-cli version                                   
arduino-cli Version: 0.0.0-git Commit: 
akos.kitta@Akoss-MacBook-Pro arduino-cli % ./arduino-cli config init --dest-dir ~/Desktop          
Config file written to: /Users/akos.kitta/Desktop/arduino-cli.yaml
akos.kitta@Akoss-MacBook-Pro arduino-cli % cat ~/Desktop/arduino-cli.yaml 
board_manager:
  additional_urls: []
daemon:
  port: "50051"
directories:
  data: /Users/akos.kitta/Library/Arduino15
  downloads: /Users/akos.kitta/Library/Arduino15/staging
  user: /Users/akos.kitta/Documents/Arduino
logging:
  file: ""
  format: text
  level: info
akos.kitta@Akoss-MacBook-Pro arduino-cli % cd ~/Desktop/foo
cd: no such file or directory: /Users/akos.kitta/Desktop/foo
akos.kitta@Akoss-MacBook-Pro arduino-cli % ./arduino-cli config init --dest-dir ~/Desktop/foo
Config file written to: /Users/akos.kitta/Desktop/foo/arduino-cli.yaml
akos.kitta@Akoss-MacBook-Pro arduino-cli % cat ~/Desktop/foo/arduino-cli.yaml                
board_manager:
  additional_urls: []
daemon:
  port: "50051"
directories:
  data: /Users/akos.kitta/Library/Arduino15
  downloads: /Users/akos.kitta/Library/Arduino15/staging
  user: /Users/akos.kitta/Documents/Arduino
logging:
  file: ""
  format: text
  level: info
akos.kitta@Akoss-MacBook-Pro arduino-cli % 

[rsora]

👍