5.5-dev max_lag support

[wsor4035]

luanti-org/luanti@4fca601

[S-S-X]

Nice addition to engine, however we want to stop and think a bit before using that.

Some time ago max lag thing had 2 problems:

• Max lag values provided by engine were very bad for this use case.
• Max lag was parsed from server status message because there was no engine API.

#193 fixed actual max lag values that are actually usable for technic.
It did also get around status message parsing but not by using engine API.

Now this PR will use engine API which is very nice but it would also return back to very bad max lag calculation done by engine, values returned by that thing are useless for reducing lag caused by technic.

See PR comments for custom method to get max lag: #193
(tldr: engine max lag will stuck at high values for way too long when insignificant but long lag spikes happen, not metric we're interested of)

[wsor4035]

closing as request not wanted