feat(users/Profpatsch/my-prelude): add builder & divisible helpers

I’ve had enough of `show & stringToText` bullshit, let’s finally
create a trivial builder contravariant module that wraps
`Text.Builder` and `ByteString.Builder` and has a naming scheme that
does not collide with anything and that I can remember in my sleep.

Plus some experiments in making `Divisible` useful with `HasField`.

Change-Id: Ie25f78226d24eadf4c35353fe9db40b7683d82c3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12955
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/Profpatsch/my-prelude/my-prelude.cabal

@@ -61,8 +61,10 @@ library
       Aeson
       Arg
       AtLeast
+      Builder
       Comparison
       Debug
+      Divisive
       Json
       Json.Enc
       Test
@@ -92,6 +94,7 @@ library
      , base64-bytestring
      , bytestring
      , containers
+     , contravariant
      , foldl
      , unordered-containers
      , resource-pool