The validator client was only able to connect to beacon nodes exposing
the exact same set of spec constants that are locally known via their
config/spec REST API. However, that set of spec constants is dynamic.
As the validator client only requires a subset of relevant constants,
this may lead to compatible specs being rejected. This patch widens the
allowed specs by only verifying that the required set of constants are
present in the spec response, ignoring any spec constants that are not
locally known, and ignoring missing spec constants that are locally
known but not included by the remote beacon node when not relevant for
operation of the validator client.
This refactoring puts the JSON-RPC and REST APIs on more equal footing
by renaming and moving things around, creating a separation between
client and server, and documenting what they are - the aim is to have a
simple-to-use base to start from when developing API clients, as well as
make it easier to navigate the code when looking for the legacy JSON-RPC
interface vs the new REST API.
* move REST client, serialization and supporting types to spec/eth2_apis
* REST stuff now starts with `rest_`, JSON-RPC stuff starts with `rpc_`,
more or less
* simplify imports such that there's a simple module to import for both
server and client
* map REST type and proc names to yaml spec more closely - in
particular, reuse operation and type names in `rest_types` to make
comparisons against spec more easy
* cleaner separation between client and server modules - modules common
between server and client such as `rest_types` and serialization move to
the spec folder - this allows the client to be built with less knowledge
about server internals
Etan Kissling
Jacek Sieka