This commit introduces a new project that builds a Jar of the
classes that have a dependency on BouncyCastle and puts it in a
subdirectory of lib (/tools/security-cli) along with the
BouncyCastle jars. This directory is then passed in the
ES_ADDITIONAL_CLASSPATH_DIRECTORIES of the CLI tools that use
these classes.

BouncyCastle is removed as a runtime dependency (remains
as a compileOnly one) from x-pack core and x-pack security.

- Move source for CertificateTool, CertificateGenerateTool and
CertGenUtils and associated tests to the new project
- Ensure that the genrated jar and bc dependencies are not bundled
in oss