add PKCS11 support (#1153)

* 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

---------

Co-authored-by: Morgan Jones <me@numin.it>
Co-authored-by: John Maguire <contact@johnmaguire.me>

.github/workflows/test.yml

@@ -67,6 +67,24 @@ jobs:
     - name: End 2 end
       run: make e2evv GOEXPERIMENT=boringcrypto CGO_ENABLED=1
 
+  test-linux-pkcs11:
+    name: Build and test on linux with pkcs11
+    runs-on: ubuntu-latest
+    steps:
+
+    - uses: actions/checkout@v4
+
+    - uses: actions/setup-go@v5
+      with:
+        go-version: '1.22'
+        check-latest: true
+
+    - name: Build
+      run: make bin-pkcs11
+
+    - name: Test
+      run: make test-pkcs11
+
   test:
     name: Build and test on ${{ matrix.os }}
     runs-on: ${{ matrix.os }}