Added basic "deprecation" support for platforms

[cmaglie]

The IDE now supports a deprecated field in the package_index.json at the platform release level:

    {
      "name": "arduino",
      "maintainer": "Arduino",
      "websiteURL": "http://www.arduino.cc/",
      "email": "packages@arduino.cc",
      "help": {
        "online": "http://www.arduino.cc/en/Reference/HomePage"
      },
      "platforms": [
        {
          "name": "[DEPRECATED - Please install standalone packages] Arduino Mbed OS Boards",
          "architecture": "mbed",
          "version": "2.0.2",
          "deprecated": true,             <--------
          "category": "Arduino",
          "url": "http://downloads.arduino.cc/cores/staging/ArduinoCore-mbed-2.0.2.tar.bz2",
          "archiveFileName": "ArduinoCore-mbed-2.0.2.tar.bz2",
          "checksum": "SHA-256:51b261ca0b11cd98f6e91d660ef2338e462c45b2ece20b527b74c13b51dbcad2",

if the latest version of a platform is marked deprecated then the whole platform is labeled as deprecated and moved to the bottom of the list.

this should discourage users from installing it, BTW no other actions are done to prevent it.

[ArduinoBot]

✅ Build completed.

Please test this code using one of the following:

⬇️ https://downloads.arduino.cc/javaide/pull_requests/arduino-PR-11508-BUILD-991-linux32.tar.xz
⬇️ https://downloads.arduino.cc/javaide/pull_requests/arduino-PR-11508-BUILD-991-linux64.tar.xz
⬇️ https://downloads.arduino.cc/javaide/pull_requests/arduino-PR-11508-BUILD-991-windows.zip
⬇️ https://downloads.arduino.cc/javaide/pull_requests/arduino-PR-11508-BUILD-991-macosx.zip
⬇️ https://downloads.arduino.cc/javaide/pull_requests/arduino-PR-11508-BUILD-991-linuxarm.tar.xz

ℹ️ The linuxarm build is still experimental and may not be always available.

[rsora]

Tested on Win and Linux and it's ok

[rsora]

(Tested successfully on Mac as well BTW 😸 )