Remove the node's bespoke configuration-file parsing

With cardano-node, the chairman, tx-generator and cardano-testnet all
routing through cardano-config, nothing parses the node configuration
file via the node's own machinery anymore. Drop:

  * instance FromJSON PartialNodeConfiguration (and all its helpers),
  * instance AdjustFilePaths PartialNodeConfiguration (path resolution
    is now done in the Adapter),
  * parseNodeConfigurationFP,

together with the imports they pulled in (including the yaml package
dependency) and the two POM tests that exercised the JSON decoding. The
PartialNodeConfiguration / NodeConfiguration model and makeNodeConfiguration
are kept: they remain the node's resolved configuration type and the target
of Cardano.Node.Configuration.Adapter.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: jasagredo

cardano-node/cardano-node.cabal

@@ -189,7 +189,6 @@ library
                       , transformers
                       , transformers-except
                       , typed-protocols:{typed-protocols, stateful} >= 1.2
-                      , yaml
 
 executable cardano-node
   import:               project-config