More sanity checks for config options

[NexiusTailer]

Some sanity checks could be added to warn about one of the examples:

• maxnpc variable exceeds the maximum number of player slots
• query is disabled but announce is enabled, so the server will not be visible in masterlist
• More checks on negative values for the most of settings which cannot apply such numbers

Other checks which also can be applied from the server start:

• scriptfiles folder cannot be created for some reason (some scripts rely on this and may work incorrectly)

[vsmxd]

Added PR: https://github.com/openmultiplayer/open.mp/pull/1097

@AmyrAhmady