* apitypes: synchronize handling of types

* signer/core/apitypes: improve array check

* apitypes: add a test for big.Int -> int32

* signer/core/apitypes: Add a test for parsing addresses from [20]byte, []byte and string

* signer/core/apitypes: add some testcases
Co-authored-by: Felix Lange <fjl@twurst.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>