Updating the Prim Ref page

[Vincent Messenet]

I've started to consolidate lists of all available rings in the library

Job completed will all rings prims normal/high/low resolutions and both official/unofficial ones

At the end I've held few prims/parts on PT and identified two official prims that could be obsoleted:
p/3-16ring1.dat released in 2019-01 with 4 files using it while we already have p/3-16rin1.dat released in 2010-03 with 6 files using it
p/7-16ring3.dat released in 2020-01 with 3 files using it while we already have p/7-16rin3.dat released in 2010-01 with 4 files using it