Add EntrypoinySecurity in addition to Entrypoint

[BBialeckiACR]

Issue 422 requests Entrypoints to be added to the spec as a resource that can be defined. As these entrypoints will have security built around them the re is an additional requirement to add EntrypointSecurity as a resource as well. Schemas for Entrypoint Security will be items such as TLS, User Identity, Digital Signature, EFS and Secure Rest such as basicAuth, formAuth, clientCertAuth, oAuth, or bearerAuth.
These are developer implemented and configured for the most part and therefore need to be resources made. To ensure there is a standard way to define security features there needs to be a defined schema for interoperatbility. These Entrypoint Security schemas will be called from within the Entrypoint definitions.