Add documentation for ANDROID_IGNORED_VARIANTS

[mformetal]

Is your feature request related to a problem? Please describe.

I just found the dependency.analysis.android.ignored.variants gradle.properties flags, which allows my very memory-hungry build to ignore a bunch of variants that we don't need or want to analyze. However, I wasn't able to find documentation for this in the wiki: https://github.com/autonomousapps/dependency-analysis-gradle-plugin/wiki

Describe the solution you'd like

Would be nice if you could document that flag and how to use! Some android developers may not know exactly what a variant is, although I imagine if they've found this plugin they have some basic knowledge.

Describe alternatives you've considered

N/A

Additional context

Thanks for making this plugin!

[autonomousapps]

Thanks for the issue. I think you're completely right that this is a gap that should be addressed.

[mformetal]

Thanks for the issue. I think you're completely right that this is a gap that should be addressed.

And thank you for the ignored variants stuff! Really makes my life a lot easier.