These outputs are called anchors, and allow
key-less anchor spends which are vsize-minimized
versus keyed anchors which require larger outputs
when creating and inputs when spending.
This should fix the bug reported in
https://github.com/bitcoin/bitcoin/pull/28246#discussion_r1371640502,
which caused the GUI to not detect the destination type of recipients,
thus picking the wrong change destination type.
Also, add missing lifetimebound attribute to a getter method.
This should cut some include bloat and seems fine to do, because
prevector exists primarily to represent scripts.
Also, add missing includes to script.h and addresstype.h
P2PK scripts are not PKHash destinations, they should have their own
type.
This also results in no longer showing a p2pkh address for p2pk outputs.
However for backwards compatibility, ListCoinst will still do this
conversion.
Make sure that nothing else can change WitnessUnknown's data members by
making them private. Also change the program to use a vector rather than
C-style array.
CTxDestination is really our internal representation of an address and
doesn't really have anything to do with standard script types, so move
them to their own file.
