KARAF-6925 - Initial attempt at supporting spring-security-crypto

[coheigea]

Some points to note:

• In jaas/spring-security-crypto/pom.xml it just depends on a servicemix bundle, I wasn't sure whether to just depend on the normal spring jar here.
• The feature I added could be reworked to remove dependency on a set version of Spring.
• scrypt, bcrypt, pbkdf2, argon2 work well.
• Remaining work: Update the default jaas file comments to show how to use it, and update the documentation.

[jbonofre]

I would use a different approach embedding spring-security as private to avoid feature dependency. Let me rework this PR.

[jbonofre]

As said, I will rework this one to avoid Spring bundles dependency and prefer spring-security embedded. I will do that tomorrow. Thanks !

[coheigea]

Thanks @jbonofre, I was just making a trivial change to the logic.

[jbonofre]

As it's an optional JAAS bundle, it makes sense to keep it as a feature (no need to use private package as it's not part of "core" JAAS). LGTM.