Statically link libortools.a into binary

[daniel-j-h]

Up till now we only had a dynamically linked libortools.so library in mason. We changed this in this commit upstream (context) which builds both a dynamically linked as well as a statically linked library. In addition

• these libraries do include debug symbols and
• have their functions put into own sections so that our linker can discard what's not needed when building the node binaries

This makes the or-tools mason package a bit bigger in size (in the hundreds of megabytes) but now we have debug binaries available. For our release node bindings we simply strip out debug symbols when linking the node binaries such that the final statically linked bindings come down to roughly ten megabytes in size.

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If this works out we need to release v1.0.3 - see https://github.com/mapbox/node-or-tools#releases