Make plugin dynamic

[fwdekker]

Randomness is, at its core, quite a simple plugin. Turning it into a dynamic plugin, thus allowing updates to complete without restarting the IDE, should be doable.

Currently, Randomness is explicitly marked as non-dynamic because the dynamic plugin system seems botched. (See #522 and #520.) As of IntelliJ 2025.1, it looks like this system is still utterly botched. Even with an extremely simple project (without any code, extensions, or... anything) dynamic reload does not work at all.