Initial configuration of repo

[drewoldag]

Applying the LINCC frameworks Python project template
Added SinusoidalLightcurve source, test, simple notebook and documentation page
Provided scaffolding for additional documentation as well as placeholder documentation to be filled later.

[drewoldag]

Note that the CI will initially fail because the version of sorcha that is available on PyPI needs to be updated. Once this PR (dirac-institute/sorcha#493) is merged, we should be in a good place to increment the version number and then the CI here will pass.

Testing was performed locally using sorcha installed from github with pip. (Not what we would want in production)