Currently, AgoraPartial only supports SLP, with this diff it also supports ALP.
SLP and ALP have the same Agora Script except for the sub-script that builds the OP_RETURN output, as well as the last few ops.
ALP doesn't use the scriptSig to signal AGR0, instead it uses the OP_RETURN via eMPP. This increases tx size a bit, but simplifies usage significantly, as e.g. no ad setup tx is necessary anymore, and offers can be created directly in a single tx.
Depends on D16745.