Pass of security, references, appendices, and acks

* Harmonize conventions for naming conferences

    * seriesinfo == name of the conference (with common acronym in
      parantheses) w/o the edition (this is the same as the year)

* Remove some redundant text about the security model of {{DPRS23}}.

* Say applications SHOULD bind the verification key to the context

* Define "steering attack" (this name should be handy later on)