Remove Timings and bundle Spark

[Villagers654]

Since timings is being deprecated and removed by Paper #8948 and its forks, it makes sense for Nukkit to follow suit and remove timings in favor of Spark.

This PR removes Timings from the server completely, and then installs Spark automatically (unless the user already has installed Spark as a plugin)

The method of installing Spark is based on Purpur #1020

[PetteriM1]

Is it intentionally only downloading Spark when the server is reloaded? Also, there should probably be a setting to disable Spark download.

[Villagers654]

To make a config change, do I have to write a PR to Languages? Or am I missing something

[PetteriM1]

To make a config change, do I have to write a PR to Languages? Or am I missing something

Yes. The default nukkit.yml is loaded from language submodule and it isn't updated automatically because that would remove all comments I think.

[Kazzuk]

Noticed a few Timings references lingering:

1. ISSUE_TEMPLATE.md
2. Server.java
3. DefaultPermissions.java