Added programmer field in debug info output

[cmaglie]

Please check if the PR fulfills these requirements

See how to contribute

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows
  our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)
• configuration.schema.json updated if new parameters are added.

What kind of change does this PR introduce?

The output of debug --info --format json now has the programmer field that contains the programmer specified with the -P flag.

What is the current behavior?

~/Arduino/Blink$ arduino-cli debug -b arduino:samd:mkr1000 -P atmel_ice --info --format json
{
  "executable": "/tmp/arduino/sketches/002050EAA7EFB9A4FC451CDFBC0FA2D3/Blink.ino.elf",
  "toolchain": "gcc",
  "toolchain_path": "/home/megabug/.arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
  "toolchain_prefix": "arm-none-eabi-",
  "server": "openocd",
  "server_path": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
  "server_configuration": {
    "path": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
    "scripts_dir": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/share/openocd/scripts/",
    "scripts": [
      "/home/megabug/.arduino15/packages/arduino/hardware/samd/1.8.13/variants/mkr1000/openocd_scripts/arduino_zero.cfg"
    ]
  }
}

What is the new behavior?

~/Arduino/Blink$ arduino-cli debug -b arduino:samd:mkr1000 -P atmel_ice --info --format json
{
  "executable": "/tmp/arduino/sketches/002050EAA7EFB9A4FC451CDFBC0FA2D3/Blink.ino.elf",
  "toolchain": "gcc",
  "toolchain_path": "/home/megabug/.arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/",
  "toolchain_prefix": "arm-none-eabi-",
  "server": "openocd",
  "server_path": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
  "server_configuration": {
    "path": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/bin/openocd",
    "scripts_dir": "/home/megabug/.arduino15/packages/arduino/tools/openocd/0.10.0-arduino7/share/openocd/scripts/",
    "scripts": [
      "/home/megabug/.arduino15/packages/arduino/hardware/samd/1.8.13/variants/mkr1000/openocd_scripts/arduino_zero.cfg"
    ]
  },
  "programmer": "atmel_ice"         <-----
}

Does this PR introduce a breaking change, and is titled accordingly?

Other information

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ba72833) 64.48% compared to head (30bd611) 64.51%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2391      +/-   ##
==========================================
+ Coverage   64.48%   64.51%   +0.02%     
==========================================
  Files         207      207              
  Lines       19593    19592       -1     
==========================================
+ Hits        12634    12639       +5     
+ Misses       5867     5863       -4     
+ Partials     1092     1090       -2     

Flag	Coverage Δ
unit	64.51% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
commands/debug/debug_info.go	67.06% <100.00%> (+0.19%)	⬆️
internal/cli/debug/debug.go	73.68% <100.00%> (+0.19%)	⬆️

... and 2 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.