Add recommendations about recording follow-up actions

[mirjak]

This is from the old appendix that is now removed from the doc. We might want to check if we still want to discuss any of these feature in the new version of the doc.

This list of feature was indicated as Phase II in RFC4053 but have
never been implemented. Therefore this list is kept for now as a
record of high-level intended features of the future liaison statement
tracking system:

o Designating an assignee; the assignee is initially a person
associated with the body (IAB, IESG, Area, WG, etc.) to which the
liaison statement is addressed, but may subsequently be changed by
an IETF participant.

o Indicating the status of the liaison statement (e.g., actions
required, actions taken, etc. Specific options TBD).

o Sending ticklers to the assignee when action is required (with
copies to whomever is appropriate).

o Changing the status of the liaison statement, the deadline, or
other attributes.

o Reassigning responsibility.

o Closing the liaison statement.

[mirjak]

The non-implemented features do relate to issue #14 and while we don't want to specify directly tooling requirements, I now wonder if we want to say something like that is is recommended to also record if and what action was taken, e.g. by linking a reply to the originally received LS or adding a comment on why no response was sent or what other action was taken. I think this can be phrased in a way that it is not directly a tooling requirement but more a recommendation for good behavior.