fix: do not override node lookup timeout concurrently

[czeslavo]

In 6455a5b, NodeLookupTimeout was added to the ruleContext, but setting its default value was added to a function that is run for every rule from RuleSet.Rules concurrently, causing a data race. This fixes that by moving setting the default outside of the concurrent code.

==================
WARNING: DATA RACE
Read at 0x00c000716728 by goroutine 56:
  github.com/daveshanley/vacuum/motor.ApplyRulesToRuleSet.func7()
      /Users/[email protected]/go/pkg/mod/github.com/daveshanley/[email protected]/motor/rule_applicator.go:664 +0x158
  github.com/daveshanley/vacuum/motor.ApplyRulesToRuleSet.gowrap1()
      /Users/[email protected]/go/pkg/mod/github.com/daveshanley/[email protected]/motor/rule_applicator.go:704 +0x54

Previous write at 0x00c000716728 by goroutine 57:
  github.com/daveshanley/vacuum/motor.ApplyRulesToRuleSet.func7()
      /Users/[email protected]/go/pkg/mod/github.com/daveshanley/[email protected]/motor/rule_applicator.go:665 +0x170
  github.com/daveshanley/vacuum/motor.ApplyRulesToRuleSet.gowrap1()
      /Users/[email protected]/go/pkg/mod/github.com/daveshanley/[email protected]/motor/rule_applicator.go:704 +0x54