Increase the number of bits of the CT rangeproofs

[stevenroose]

Since we're reducing the fee rates, we might as well make this change that's been talked about for a while.

[instagibbs]

right, in lieu of bulletproofs(long deferred) this may be preferable.

[allenpiscitello]

We should consider waiting on doing this until after the lower fee has been deployed in Liquid.

[stevenroose]

This has been implemented.