feat(users/Profpatsch/mailbox-org): list & update filters

One step closer towards a declarative description of filters.
In the end, the filters should be updated by their `rulename` field.

This implements a simple scheme where we list all filters, parse some
of their fields, use those fields to determine whether we want to
change the filters, and then only update the filters where we changed
something.

Unfortunately, we can only update the filters one-by-one (a common
mistake in APIs).

Pulls in some modules for Json parsing that I like to use, and an
`ErrorTree` abstraction over `Error` and `Data.Tree`.

Change-Id: Iea45d5aa0a3fee7ec570f06d3e77009769091274
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7720
Autosubmit: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

users/Profpatsch/mailbox-org/mailbox-org.cabal

@@ -10,11 +10,14 @@ executable mailbox-org
     build-depends:
         base >=4.15 && <5,
         my-prelude,
+        exec-helpers,
         random,
         http-conduit,
         http-client,
         aeson,
+        aeson-better-errors,
         bytestring,
-        process
+        process,
+        containers,
 
     default-language: Haskell2010