Make radius_attrmap() take the "update" section itself

so that we can use it in unlang
Fix typo
Make attribute references use 'User-Name = &Filter-Id'
Enforce operators in update sections

Can only be comparison, set, etc.
Added radius_map2vp function

which should be the default callback from radius_map2request
Use correct talloc ctx

and set vp->op, so that radius_map2request doesn't have to
Initialize vp->type

So that it's clear what data type it is
Fix radius_map2request()

So that it loops over the list only in debug mode

and so that it doesn't erroneously free vp
Make the "update" sections more generic.

The new template / map code does a ton of memory allocations,
but it's more generic than the old radius_update_attrlist()
function.

The template / map code largely duplicated the functionality
of radius_update_attrlist(), but with different code.
We've deleted the old code, and now use the new code for "update"
sections.  The benefit is that we can now do:

	update {
		reply:Filter-Id := &request:User-Name
	}

And it will work.  This is more generic than before.

As a bonus, the old 2.x "update" sections still work, too