Factor out the arduino-cli `legacy` package

[ubidefeo]

Arduino CLI embeds some legacy code which should be factored out and/or cleaned up.

• provide an initial assessment of the components to delete
• delete and run tests to check for regressions
• build Arduino Builder at every step and add to Java IDE to test for failure
• repeat until all Legacy is removed

[umbynos]

This needs to be split in subtasks