Updated algorithm to split aoi when no linear features

[Sujanadh]

Changes

• refactored existing algorithm to allow splitting the aoi when no linear features are present by clustering according to the number of buildings used
• used k-means clustering

Issue

• Fixes Error handling if no linear features are included in data extract #29
• Fixes Limit the choices to only major important highways #32
• Fixes Simplify geometries (verticies) for generated task boundaries fmtm#1151 by another means, with Generate boundaries in splitting algorithm with Polygon Topology #24 still pending

[Sujanadh]

• looking for other issues to solve

[Sujanadh]

I think i overdid the clustering twice, so removed it.

[Sujanadh]

• simplified the task boundaries; related to #1151
• removed hardcoded buildings number

[Sujanadh]

• fixes Limit the choices to only major important highways #32

[spwoodcock]

This is excellent work.

I just fixed the tests.
The update also also appears to have fixed an issue where some task areas were generated as multipolygons (i.e. with holes) 👍
It mainly reduces the number of task areas generated, which is likely a good thing (as the buildings are better distributed amongst areas).

Merging 🎉