test HSMSigner on Windows

[lukpueh]

HSMSigner is tested on GitHub using SoftHSM. Installation of SoftHSM on Windows (via chocolatey) turned out to be quite flaky (see #520) and was disabled in fbf2d7f of #542.

Let's explore if there there are more stable ways of testing this on Windows! Maybe via "SoftHSM2-for-Windows"? (see #520 (comment))