Remove code from AppInitParameterInteraction() that simply reads a config value into a global

[jnewbery]

eg https://github.com/bitcoin/bitcoin/blob/8021392b825c74312173f15eb937ba6d4aec3841/src/init.cpp#L1114

[jnewbery]

My thinking has changed a bit on this. init.cpp should be reading the config values and using them as arguments when constructing the components, eg https://github.com/bitcoin/bitcoin/blob/d0852f39a7a3bfbb36437ef20bf94c263cad632a/src/init.cpp#L1405-L1406.