Remove obsolete xGRIB 0.2.0.0 metadata

[pob220]

Follow-up to #1392 and the maintainer guidance there.

Removes the seven superseded xGRIB 0.2.0.0 metadata files from the Alpha catalogue. The seven xGRIB 0.2.3.1 target entries remain unchanged.

• Deletion-only commit based directly on current OpenCPN Alpha
• 7 obsolete metadata files removed
• Regenerated candidate catalogue contains seven xGRIB entries at 0.2.3.1 and zero entries at 0.2.0.0