add dao which takes care about all CRUD operations on storage
remove blockchain state since everything is stored on change
remove storage operations from structs(entities)
move structs to entities package
It makes very little sense having pointers here, these structures MUST have
some kind of key and this key is not gonna be wandering somewhere on its
own. Fixes a part of #519.
It reduces heap pressure a little for these elements as we don't have to
allocate/free them individually. And they're directly tied to transactions or
block, not being shared or anything like that, so it makes little sense for
them to be pointer-based. It only makes building transactions a little easier,
but that's obviously a minor usecase.
