Change the directory of the configuration files

[matteosuppo]

If you install the arduino cli, the default directory
of the configuration file is the location of the executable
This is not an ideal configuration for linux or windows

With this commit the configuration file is searched in the
default configuration folder for each system

[CLAassistant]

All committers have signed the CLA.

[cmaglie]

I see that, on linux, the library searches in ~/.config/.... and /etc/xdg/....

~/.config/arduino15 may have been a valid alterantive if used from the beginning but since we used ~/.arduino15 to store everything I'd like to continue to use that one. Also /etc/xdg seems a bit overkill to me, why the extra xdg sub-folder? /etc/arduino-cli.conf seems enough...

[cmaglie]

Let's implement here some ideas from: #30
To recap some points:

1. We should look for a configuration in some predefined places, for example on Linux:

• /etc/
• ~/.arduino15/
• ${pwd}

those directories are listed in increasing order of priority and any config file found should override the previous one (I mean the options defined in ${pwd} should take priority on the ones in /etc for example).

2. we can navigate parent folders for ${pwd} to search for a config file, this would allow to make a per-project configuration.

and this is added by me:

3. we should consider a better future-proof name for the config file like: arduino-cli.conf so we have a nice /etc/arduino-cli.conf instead of /etc/.cli-config.yaml

[bxparks]

Do we need to worry about $arduino_ide_dir/portable, as described in https://www.arduino.cc/en/Guide/PortableIDE ? I don't use ~/.arduino15, because I keep multiple versions of the IDE around for testing, and I don't want one version of the IDE clobbering the files and configs of another version.

[cmaglie]

@bxparks we pushed forward portable support here: #123

Also we started bundling the cli in the official Beta IDE, at the moment arduino-cli detects if it's bundled with the IDE and also if there is a portable folder:

~/Code/arduino/build/linux/work$ ls -l
total 29272
-rwxr-xr-x  1 cmaglie cmaglie      882 feb  1 10:05 arduino
-rwxr-xr-x  1 cmaglie cmaglie 13822120 feb  1 10:05 arduino-builder
-rwxr-xr-x  1 cmaglie cmaglie 16000485 feb  1 10:05 arduino-cli
-rwxr-xr-x  1 cmaglie cmaglie     5161 feb  1 10:05 arduino-linux-setup.sh
drwxr-xr-x 13 cmaglie cmaglie     4096 feb  1 10:05 examples
drwxr-xr-x  4 cmaglie cmaglie     4096 feb  1 10:05 hardware
-rwxr-xr-x  1 cmaglie cmaglie     9796 feb  1 10:05 install.sh
drwxr-xr-x  4 cmaglie cmaglie     4096 feb  1 10:05 lib
drwxr-xr-x 21 cmaglie cmaglie     4096 feb  1 10:05 libraries
drwxr-xr-x  6 cmaglie cmaglie     4096 feb  1 10:05 reference
-rw-r--r--  1 cmaglie cmaglie    87826 feb  1 10:05 revisions.txt
drwxr-xr-x  4 cmaglie cmaglie     4096 feb  1 10:05 tools
drwxr-xr-x  4 cmaglie cmaglie     4096 gen  3 17:15 tools-builder
-rwxr-xr-x  1 cmaglie cmaglie       86 feb  1 10:05 uninstall.sh
~/Code/arduino/build/linux/work$ ./arduino-cli config dump
proxy_type: auto
sketchbook_path: /home/cmaglie/Workspace/sketchbook-cores-beta
arduino_data: /home/cmaglie/.arduino15
board_manager:
  additional_urls:
  - http://arduino.esp8266.com/stable/package_esp8266com_index.json

~/Code/arduino/build/linux/work$ mkdir portable
~/Code/arduino/build/linux/work$ ./arduino-cli config dump
proxy_type: auto
sketchbook_path: /home/cmaglie/Code/arduino/build/linux/work/portable/sketchbook
arduino_data: /home/cmaglie/Code/arduino/build/linux/work/portable
board_manager: null

BTW we barely tested the "portable" scenario, (for example now I noticed the board_mager: null in the config dump) so it may require some more work.

[matteosuppo]

In this latest batch of commits I implemented the following:

we can navigate parent folders for ${pwd} to search for a config file, this would allow to make a per-project configuration.