Deal with long Island Sound in relation to VPU and the network.

Long Island Sound is coded as being part of region 0203 and all the rivers flowing into it are in 0110.

This introduces a huge number of cross-region connections that are unnecessary.

One solution is to create a list of flowlines in 0203 that should be in 0101.

To do this, we would collect all flowlines downstream of the 0110 and downstream of the one in 0203 higlighted here in red.

They would go into a small sidecar dataset that would get pulled in whenever working with vpu 0110 in order to remove them from consideration.