Clarify Members Storage Facilities

[roberthunt]

Ignoring the fact that the rules around members boxes are a bit ambiguous at the moment (which should be cleared up when the trustees revisit the rules) we should probably clarify the rules around the things we do have.

• The members storage room is for members boxes only, items outside the members boxes will be moved to the large project shelving.
• A sheet store has been created in the workshop for the temporary storage of sheet material for projects in progress.
• Clarify the exact process around using the LPS and sheet store.

I'll add additional comments to this issue in the near future.