feat: sql handlers for custom media types

* test text/html and drop HtmlRawOutputSpec.hs
* all tests passing, removed all pendingWith
* make functions compatible with pg <= 12
* move custom media types tests to own spec
* anyelement aggregate
* apply aggregates without a final function
* overriding works
* overriding anyelement with particular agg
* cannot override vendored media types
* plan spec works with custom aggregate
* renamed media types to make clear which ones are overridable
* correct content negotiation with same weight
* text/tab-separated-values media type
* text/csv with BOM plus content-disposition header

test/spec/SpecHelper.hs

@@ -15,6 +15,7 @@ import Data.CaseInsensitive (CI (..), mk, original)
 import Data.List            (lookup)
 import Data.List.NonEmpty   (fromList)
 import Network.Wai.Test     (SResponse (simpleBody, simpleHeaders, simpleStatus))
+import System.IO.Unsafe     (unsafePerformIO)
 import System.Process       (readProcess)
 import Text.Regex.TDFA      ((=~))
 
@@ -340,3 +341,6 @@ getInsertDataForTiobePlsTable rows =
   JSON.encode $ fromList $ [TiobePlsRow {name' = nm, rank = rk} | (nm,rk) <- nameRankList]
    where
      nameRankList = [("Lang " <> show i, i) | i <- [20..(rows+20)] ] :: [(Text, Int)]
+
+readFixtureFile :: FilePath -> BL.ByteString
+readFixtureFile file = unsafePerformIO $ BL.readFile $ "test/spec/fixtures/" <> file