Discover additional JDKs on Windows (#140)

[Okeanos]

Adds support for auto-discovery of additional popular JDKs on Windows. Vendors of JDKs for Windows apparently pick their own (default) location to install into and do not re-use the Oracle default of C:\Program Files\Java.

This adds support for automatically discovering the following OpenJDK implementations:

• Amazon Corretto
• Azul Zulu
• BellSoft Liberica
• Eclipse Adoptium

Fixes #140

Additional comments:

Gradle & e.g. JetBrains' IDEs both use the Windows registry to look up JDK locations. However, adding support for that would have:

• changed the existing simple implementation a lot
• introduced a sizeable amount of Windows platform code
• not yielded a lot of benefit, see attached screenshot for what a registry looks like after installing a variety of JDKs
  • in particular: the registry key structure is non-consistent across vendors, leading to a lot of extra steps to parse as many as possible
  • occasionally existing keys (particularly the Oracle Java defaults) are overwritten by other vendors (usually selected optionally in the installers), leading to missed detections compared to simple file system checks
  • some vendors (e.g. Amazon) do not create their custom registry keys at all

I picked a "random" selection of OpenJDK Vendors that came to mind for this. If other vendors (e.g. Microsoft, IBM (OpenJ9), …) are of interest I can check them out and add them as well.

The implementation is "naive" (just add the folders to scan) on purpose to keep things simple.

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