Added ability to change max players by a command

[JavierLeon9966]

Introduction

Sometimes we want to limit the number of players that can join our server without needing to restart it and have to make them rejoin it and possibly make unwanted players join in the process. This pull request adds the /setmaxplayers command to change the max player count during runtime.

Relevant issues

None

Changes

API changes

None

Behavioural changes

None

Backwards compatibility

None

Follow-up

Requires translations:

Name	Value in eng.ini
commands.setmaxplayers.success	Set max players to {%0}.
commands.setmaxplayers.success.lowerbound	(Bound to current player count)
commands.setmaxplayers.usage	/setmaxplayers <maxPlayers>
pocketmine.command.setmaxplayers.description	Sets the maximum number of players for this server.
pocketmine.permission.command.setmaxplayers	Allows the user to change the max player count

Tests

TODO

[dktapps]

I feel like this is better suited to a plugin

[SOF3]

First, the changes to Server.php must be merged to make this possible through a plugin.

Second, this is a BC break. There might be plugins assuming an new SplFixedArray($server->getMaxPlayers()) and end up overflowing.

[dktapps]

First, the changes to Server.php must be merged to make this possible through a plugin.

I hadn't actually noticed this wasn't currently possible. In that case, we should probably add some actual APIs rather than using configs for this.

I still don't think a command for this is appropriate for the core though.

[JavierLeon9966]

I hadn't actually noticed this wasn't currently possible. In that case, we should probably add some actual APIs rather than using configs for this.

I still don't think a command for this is appropriate for the core though.

At first I considered making Server->setMaxPlayers() with validation checks, but then I realized Server had no set methods and it used the config instead, so I decided to opt for that for consistency.

Second, this is a BC break. There might be plugins assuming an new SplFixedArray($server->getMaxPlayers()) and end up overflowing.

I also considered limiting it to Limits::INT32_MAX because Minecraft uses that for the max player count and anything above that goes into the negatives, but I chose PHP_INT_MAX to be consistent with the config which has no bounds checks.