deskutils/presage: New port

Presage is an intelligent predictive text entry system.

Presage (formerly known as Soothsayer) generates predictions by modelling
natural language as a combination of redundant information sources. Presage
computes probabilities for words which are most likely to be entered next by
merging predictions generated by the different predictive algorithms. Presage’s
modular and extensible architecture allows its language model to be extended
and customized to utilize statistical, syntactic, and semantic predictive
algorithms.

WWW: https://presage.sourceforge.io/

This port will be required by maliit-keyboard, the defacto standard
virtual keyboard for Plasma Wayland Desktop