feat(sidereal): create nearest, linear, and cubic regridders
feat(sidereal): create nearest, linear, and cubic regridders

Creates the SiderealRegridderNearest, SiderealRegridderLinear,
and SiderealRegridderCubic pipeline tasks that implement
simple methods for interpolating onto a fixed sidereal grid.

radiocosmology/draco,radiocosmology/draco