Patch Notes: Regional prosperity

Towns

When players are active at the towns of a region, the region becomes more prosperous. This is true for the Iliac Bay and for all the provinces of Tamriel.
The prosperity of a region adds a small bonus to the Prosperity of each town in it. The bonus is 0 to 5.
An action counts three days after its day. Thus a late Watch claim or a late sale also counts.
A region that players do not visit goes back to its usual level. Its prosperity becomes half each four days.
This is for online play.

FOUNDATION: the world's atlas, the regions' clock, property and land as data - and two audits by @Lattymoy in #1489

Full Changelog: app-v0.1.13687...app-v0.1.13698