BIP-0158: remove extended filter, remove txid from regular filter, reparameterize gcs params

In this PR, we propose a set of changes to BIP 158 (block filter digests) to reduce the size of the filters, while maintaining the same level of utility for wallets and applications that seek to utilize this new(ish) BIP. A rundown of the new changes follows:

• The txid has been removed from the regular filter, as in many cases just matching on the pkScript, then checking the block locally after it matches for the precise txid match is enough. I've implemented this new logic in lnd (as we're the primary user of this new functionality), and the changes were rather contained, so it shouldn't be a big change application logic wise.
• The extended filter has been removed as there isn't really a clear use case for them atm, and they increase the index size for a full node.
• The gcs parameters have been re-parameterized, to set the fp rate independently from the modulus used when hashing the set of N items down to a single range. As a result, the filter sizes have shrunk a bit as we can save a bit or two for each element.