OPNWAF: describe new/changed features

[AdSchellevis]

Important notices

Before you add a new report, we ask you kindly to acknowledge the following:

• [x] I have read the contributing guide lines at https://github.com/opnsense/docs/blob/master/CONTRIBUTING.md
• [x] I have searched the existing issues and I am convinced that mine is new.

Is your feature request related to a problem? Please describe.

New and changed features:

• [ ] per vhost HeaderSecurity setting
• [ ] per vhost TLSSecurity profile setting