Create Big Cannons: Equally Opposite

*"CLEAR THE DECK OR TURN TO JELLY!"* ### Changes: - Firing a cannon or autocannon now produces a spherical shockwave and a jet of hot gas originating from the muzzle. - Shockwaves & gas jets deal damage and forces to entities & sublevels. - New death messages have been added: Being incinerated by standing in front of the cannon at a close range; Getting obliterated by the gas jet by standing in front of the cannon beyond the incineration range; Having your organs liquefied with a shockwave by standing too close to the cannon when it fires. - Sable physics objects are affected by shockwaves. - Blocks and Sable physics objects can shield you from shockwaves and gas jets. - Shockwaves reflect off of blocks and sublevels, making the firing of a cannon in an enclosed space hazardous for the well-being of anything within the space. - Entity damage caused by shockwaves & gas jets is enabled by default in the config, but can be turned off in the config by setting `disableMuzzleBlast = false` or by using the `/gamerule cannonBlastDamage false` command in-game to for a specific world.