port NAC to security v2

This commit is based on Lei Pi's commit, which changed certificate version from v1 to v2.
The later changes fix some bugs and refactor algo part of the library to get rid of cryptopp.

Change-Id: I3be7e0341fe85ee69f1b5f1c3ed7421a6c61d0b5
diff --git a/.gitignore b/.gitignore
index 4629c34..349ba35 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@
 build/
 VERSION
 unit-tests.conf
+.vscode