Add equoList support for p2deps

[nedtwigg]

Let's say you have this block:

apply plugin: 'dev.equo.p2deps'
p2deps {
  into 'compileOnly', {
    p2repo 'https://download.eclipse.org/eclipse/updates/4.26/'
    install 'org.eclipse.platform.ide.categoryIU'
  }
  into 'buildshipCompileOnly', {
    gradleBuildship()
  }
}

Right now, if you want to debug the dependencies inside either of the p2deps blocks, you have to copy it into an equoIde block before you can run equoList on it.

It would be better if equoList could take an argument like --p2deps=compileOnly. Important to note that there are lots of projects where p2deps is applied but equoIde isn't, and the equoList task ought to be available in both places.