* add PKCS11 support
* add pkcs11 build option to the makefile, add a stub pkclient to avoid forcing CGO onto people
* don't print the pkcs11 option on nebula-cert keygen if not compiled in
* remove linux-arm64-pkcs11 from the all target to fix CI
* correctly serialize ec keys
* nebula-cert: support PKCS#11 for sign and ca
* fix gofmt lint
* clean up some logic with regard to closing sessions
* pkclient: handle empty correctly for TPM2
* Update Makefile and Actions
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Co-authored-by: Morgan Jones <me@numin.it>
Co-authored-by: John Maguire <contact@johnmaguire.me>
