Improve building for E&L

Right now deployables are placed poorly on rough ground (they float or sink).
-Add a mode (key toggle or modifier) where deployables adjust to the ground. So on terrain they actually follow the terrain instead of staying perfectly flat.
-Allow proper stacking for some items, like hesco barriers on hesco barriers. Can be mode too (key toggle or modifier).
-Add pre-built structures (like small shelters/covers for Reserve) so instead of placing 10–20 separate deployable structures, you place one complete one, improving both usability and performance.
-Add a multi-place system where you can place 2–5 connected deployables at once:
it looks like multiple objects but is placed in one action and in one object to save performance. Still consumes all required deployables (no duplication or free deployables, like to build right away 3 wall lane you need 3 deployables in your toolbox. In our templates, we often use 2 or 3 deployables in a row, so this will really help).

I'm not sure but it can definitely help so server don't load that much