Select isolated dynamic asteroids

A context menu and menu button to select dynamic asteroids that are isolated.

Space Engineers generally only generates the .vx2 file and a the Asteroid entity in the SANDBOX_0_0_0_.sbs when a dynamic asteroid has been modified (either by a player mining, or meteor hit).

Over the long term, this causes two issues.

• The game size increases (larger server footprint, storage and memory), and more downloads for players.
• Asteroids are mined out, and have no useable ore left.

Dynamic asteroids with static content can be deleted, and Space Engineers will automatically generate a new dynamic one in it's place, effectively resetting the asteroid back to it's pristine state.
However, this should only be done when there are no other entities in the bounding box of the asteroid. No floating items, players, ships or stations. Otherwise players can be killed or trapped. Ships can be destroyed.

Only Dynamic asteroid entities should be selected. I believe this can only be determined by the voxel storage name pattern. Asteroid_##_##_##_#_##########.vx2
And only asteroids where there are no other items within its bounding box.

Start by locating the world-entity and selection UI handling for SANDBOX_0_0_0_.sbs and voxel storage names matching Asteroid_#################.vx2. Verify how bounding-box occupants are detected before implementing the context-menu or menu-button action; done means only isolated dynamic asteroids are selected and unsafe asteroids are excluded.