Folia support about mapmodcompanion

[turikhay]

We don't rely on entities, chunks or basically anything that would require us to use single-thread Bukkit scheduler. That's why enabling Folia support may be as easy as simply marking our plugin as folia-supported: true.

But Folia isn't stable yet, and we don't even have publicly available builds of it (thus, no E2E tests yet).

[turikhay]

I've created folia branch for those interested in this. Download the build here: gradle-build.zip.

It worked, but required the following changes in the code:

• Replaced Spigot API library with Folia Dev API
• Bumped Java version of Spigot plugin to 17
• Replaced runTaskLater(...) with getAsyncScheduler().runDelayed(...) (should probably move to short-lived thread pool to eliminate need in Paper API?) (upd: #74)
• Locked buildSrc jackson dependencies to 2.12.7 (due to spigradle) (upd: removed entirely in #73)
• Added folia-supported: true to plugin.yml (upd: #75)