Full block Conveyors and Connectors, add airtightness

As it stands: ========================================

1. airtight conveyors need to be a junction

2. conveyor junctions are airtight, but have 6 different connections that they have to calculate

3. people spam conveyor junctions because they are also great for holding grids together

4. too many conveyor junctions cause sim speed issues

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What I propose: =====================================

1. make a full-block variant (airtight version) of the connector, conveyor tube, and conveyor corner

2. make an armored conveyor tube and corner that would be more expensive, but wouldn't detract from normal armor

3. keep the existing conveyor tube and corner, as their collisions are used in compact designs

4. add some sort of warning to players to reduce how many junctions there are, to help themselves and everyone else from lagging each other or creating desync issues (it wont outright prevent these, but reduce it instead)