Add fill modes in `bs.block:fill_block`

[theogiraudet]

Currently, bs.block:fill_block only supports setblock modes (replace, destroy, keep) and not hollow and outline. This may be good addition for a future update.

[aksiome]

I think we should use separate functions (like in word edit, wall, outline, faces, ...), or an other shape parameter for this . This is because the user might want to use the strict mode and the outline one at the same time. Ideally, the "shape" should have nothing to do with the setblock mode