Correct boundary levels for Uganda and more countries

Changes since 2.11.0.

#Fixed

• Uganda's boundaries. Asking for Uganda's regions or districts now gives the 4 regions and the 137 districts. Before, the source data listed the regions as "Unknown" and put 2006 counties where the districts should be, so maps "by district" or "by region" in Uganda started from the wrong layer. Uganda's levels are now region, district, county and sub-county.
• Unit names for more countries. Boundaries the source listed as "Unknown" now carry their real names: districts and sectors in Rwanda, zones and woredas in Ethiopia, wards in Tanzania, regions in Somalia and Malawi, and communes in Burundi.
• Several steps at once. When OrionAI starts more analysis steps than can run together, the extra step now waits for one to finish instead of failing.

#Improved

• Large watersheds. Terrain and watershed steps over a very large area (for example, everything upstream of the Owen Falls Dam at Jinja) try again on a coarser grid instead of failing, and the result says which cell size was used.
• Fewer wasted steps. When OrionAI names a step's inputs loosely (for example "points" and "polygons" for selecting points inside an area), Orion now works out which is which instead of returning an error.