Create a vcpkg issue to get maths vc-packaged

[sebsjames]

morphologica is vc-packaged, mathplot should be too, but first, this repo will need to be vc-packaged.

[sebsjames]

0e182d0 changes the vcpkg.json name to sebsjames-maths

[sebsjames]

Ping @miyanyan and @rremilian - I created a new package request for this repo: microsoft/vcpkg#46321