test(spec): inline config into test suite

Previously, information about each test-suite was repeated in 3 separate
places:
- as a label and as implicit knowledge in the test-suite itself,
- as a comment in Main.hs, and
- as a configuration in SpecHelper.hs.

With this change, there will be a single source of truth in the test
suite itself. This will allow a single test-suite to easily test
multiple different configurations.

test/spec/Feature/Query/InsertSpec.hs

@@ -1,7 +1,6 @@
 module Feature.Query.InsertSpec where
 
 import Data.List              (lookup)
-import Network.Wai            (Application)
 import Network.Wai.Test       (SResponse (simpleHeaders))
 import Test.Hspec             hiding (pendingWith)
 import Test.Hspec.Wai.Matcher (bodyEquals)
@@ -14,8 +13,8 @@ import Text.Heredoc
 import Protolude  hiding (get)
 import SpecHelper
 
-spec :: SpecWith ((), Application)
-spec = do
+spec :: SpecWithConfig
+spec withConfig = withConfig baseCfg $ do
   describe "Posting new record" $ do
     context "disparate json types" $ do
       it "accepts disparate json types" $ do