* Redesign snap1 message GetTrieNodes argument prototypes
why:
A list of sub-objects `seq[SnapTriePath]` is more intuitive to work with
than an opaque definition `seq[seq[Blob]]` because the inner object
`SnapTriePath` object has a dedicated inner structure (for how to
interprete `seq[Blob]`.)
* Collect some public constants into `constants.nim` file
* Reorg `hexary_paths.nim`
why:
+ Collecting nodes following a partial path properly ending at an
extension node failed to collect this last node.
+ Merged the nodes collecting algorithm for persistent and in-memory
into a single generic function `hexary_paths.rootPathExtend()`
info:
Extracted common tasks to `hexary_nodes_helper.nim`
* Implement `StorageRanges` message handler for snap/1 protocol
33023aaf39