update: to 1.20.3

[thakyZ]

Fixed a bunch of issues, such as:

• possible null reference exceptions.
• waypoints not being shared when freshly created.
• should fix the crashing issues people have been having, not sure though, hard to replicate.
• streamlined packets to only needing one kind.
• I will be having a mod post for this until you merge this, as I would like to have it on my server.

[thakyZ]

Link to the mod db posting: https://mods.vintagestory.at/show/mod/19704

[MaLiN2223]

Sorry I missed your PR, could you fix conflicts and ping me?