Added Full Earth Model stages to repository

Stage 1: Completed mesh of the edge of the disk of the crust
Stage 2: Completed mesh of the top of the disk of the crust
Stage 3: Completed mesh of the bottom of the disk of the crust
Stage 4: Completed mesh of the spherical crust, crust/mantle and
mantle/core boundaries
Stage 5: Finished surface meshing
Stage 6: Meshed volume 9.
Added subduct_8_stage7

Finished meshing volumes, added arbitrary side set 1
Added subduct_8_stage8

Stage 8 - completed addition of BCs as detailed in mesh_info.txt