Selections feature

Hello it would be great to have an special tool that would allow selecting different parts of the meshes either by clicking on the 2d space or 3d selecting invidual polygons or using free selection lasso/box/circle. The selection could also have implemented quick turn off/on feature and inversion function so it would allow to paint selectively over a chosen area of the mesh.
Also quick mask could be a good idea to be implemented, so similarly to the selection feature from above a mask that would be possible to turn on/off quickly to allow user to limit painting over current layer

The issue does not name files, tests, or entry points. Start by locating the mesh-painting and viewport selection code, then define the scope for polygon, lasso, box, circle, inversion, and quick-mask behavior; done should include the agreed selection and masking interactions.

Written by the indexing model from the issue text.