Pedersen commitment example in c++ (#397)

* initial commit

* random elliptic points

* initial complete example

* public random seed to prevent knowing dlogs

* cleaned up code

* add README

* Update examples/c++/pedersen-commitment/README.md

Co-authored-by: Jeremy Felder <jeremy.felder1@gmail.com>

* updates to PR comments

* codespell compliance

* corrected terminology in README

---------

Co-authored-by: Jeremy Felder <jeremy.felder1@gmail.com>

examples/c++/pedersen-commitment/compile.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# Exit immediately on error
+set -e
+
+rm -rf build
+mkdir -p build
+cmake -S . -B build
+cmake --build build