Refactor location module to include response formatting

* Move concurrent query execution into dbExecAll function
* Add custom response formatting through route labels. For each query in the set, there is an associated label, which will then be used to identify the corresponding result in the response JSON object. For example:
	- labels = [ "a", "b" ]
	- querySet = [ squel.select().from('y'), squel.select().from('x') ]
	- response = { "result" : { "a" : { // result for query a }, "b" : { //result for query b } }

Signed-off-by: João Victor Tozatti Risso <jvtr12@inf.ufpr.br>