feature/magnification

[rhayes777]

Compute magnification of a shape in the source plane

from autoarray.structures.triangles.shape import Circle
from autolens.point.solver.shape_solver import ShapeSolver

solver = ShapeSolver.for_grid(
    grid=grid,
    pixel_scale_precision=0.01,
)
magnification = solver.find_magnification(
    tracer=tracer,
    shape=Circle(
        0.0,
        0.0,
        radius=0.01,
    ),
)