Explain better why these information elements are needed

[mirjak]

Feedback from Wes:

 The changelog says you're removing a bunch of field names from the
 document, but then section 2.1 has a bunch of defined field names.
 And the list of field names is a bit hard to read.  Reading it multiple
 times made me realize what the point was, but I think it could use a
 higher level introduction stating that all LSes need important
 elements for delivery that include the sending organization (From:),
 the contacts at that organization (From-Contact:), ......

[mirjak]

Yes these are not supposed to be “field” names (of a tool) anymore but rather required information. I can add another sentence or two to say it simply does work without this information.

The paragraph before these lists says:

"Any liaison statement, however,
will always contain certain information, much as a business letter
does. In order to be able to process and record these statements
in the IETF, the information should include the following:”

I already added “in order to process and record these statement in the IETF” part for that purpose compared to the original text, but I guess I can try to phrase this entirely differently to make things more clear.

[mirjak]

@hardaker do you think we need to say more?