[RZERC] RZERC document housekeeping

[Peter Koch]

Dear RZERC members (and support staff),

since the 'RZERC Operational Procedures' document incorporates the
section on the RZERC chair that was previously a separate document
(dated 28 Feb 2017) and since we also amended the text slightly (voting
periods), I'd suggest we do keep the earlier document on the website,
but mark it 'obsolete' and/or 'superseded by the RZERC Operational Procedures
document' in the document archive.  We might also, at some later stage,
introduce document numbering.

Regards,
  Peter