box: add check against setting box.cfg options to inf and nan

Setting a box.cfg option to inf or nan can result in a crash or invalid
behavior. For example, setting `box.cfg.checkpoint_interval` to 0/0
triggers an assertion failure. Let's add a check against inf and nan for
all options. These special numbers don't make any sense as configuration
option values anyway.

Closes #4962

NO_DOC=bug fix