Allow customizing verb expansion strategies

[liggitt]

"if the user does an update, also allow patch", etc

currently hardcoded:

audit2rbac/pkg/process.go

Lines 35 to 40 in 78308e5

	VerbExpansions: map[string][]string{
	"watch": []string{"get", "list"},
	"list": []string{"get", "watch"},
	"update": []string{"get", "patch"},
	"patch": []string{"get", "update"},
	},