Add new communication endpoint to node- RPC Sidecar

[SaiProServ]

Node should be able to serve raw data from storage.

[rafal-ch]

Requirements:

• Binary protocol for speed and possible avoidance of reserialization
• Binary protocol as a hint that the interface is not for general consumption
• Allow "raw" reading, client is responsible for implementing "higher level" read operations
  • for example: there's not gonna be a "GetBlock" operation, client will need to ask node for all the details it needs to provide external caller with the block data (block header, transfers, etc.)
• Writing limited to: put_deploy (put_transaction) - no "raw" writing, hence no risk of corruption of the data
• Speculative execution "service"
• Backpressure (per client, allow fixed number of requests at a time + allow for limited number of clients)
• Access control is on the IP level

cc: @marc-casperlabs @Fraser999

[rafal-ch]

Node side:

• [x] Juliet server in node (mvp)
• [x] Add some kind of connection limiter
• [x] Respect config
• [x] Add metrics
• [x] Take care of node_startup_instant
• [x] Cover with tests
• [x] Support queries that are handled by in-memory data, not storage (/status, /peers, ...)
• [x] Support PutTransaction and PutDeploy
• [x] Support GetAuctionInfo request which accesses the tracking copy

Sidecar side:

• [x] Extract RPC interface from node to sidecar
• [x] Rip RPC from node
• [x] Sidecar needs to use juliet instead of effectbuilder
• [x] Work on a single RPC call (get_deploy) / fix issues and edge cases
• [x] Continue with other Get endpoints
• [x] Add support for put_transaction & speculative_exec
• [x] Support for legacy (bincode-encoded) data - cover with test
• [ ] Update GetAccountInfo (deprecate and change to GetAddressableEntityInfo or smth)

[rafal-ch]

Regarding the in-memory data that is used in the RPC queries, here's the summary from @jacek-casper: https://gist.github.com/jacek-casper/9dce32c2e4b0282efd497f6e7abffaba

[rafal-ch]

Updated todo list:

• [x] support binary port config
• [x] add metrics
• [x] implement event system in binary port component
• [x] add some kind of connection limiter
• [x] add bytesrepr tests
• [x] add tests coverage
• [x] cleanup (especially, remove all remaining references to RPC server from node docs, comments, etc.)
• [x] update changelog
• [x] update NCTL and casper-test to use sidecar
• [ ] Review types moved to casper-types - maybe we don't want to expose all of them and can find some alternative representation
• [x] Support fallback to legacy DB
• [ ] Fix GetAccountInfo (it's not working on feat-2.0: Account -> AddressableEntity)
• [x] Fix GetAuctionInfo requests
• [x] Implement info_get_trie in sidecar
• [x] move sidecar_module to event stream sidecar (integrate with ecosystem team)
• [x] Versioning of RPC protocol (separate from node protocol version, can stay as semver, but it can be a single integer as well)
• [x] fix casper-test issue related to "early block return"

Additional TODOs after the first review meeting:

• [x] Response should be enveloped and self-describing - it should contain the copy of the request, payload type and error information

  
  // Something like...
  enum PayloadType {
  GetX,
  GetY,
  BlockV1, // Versioning
  BlockV2,
  TryAccept,
  Etc,
  Error,
  }

struct BinaryResponse { request: BinaryRequest, payload_type: PayloadType, payload: Vec, }

* [x] `AllValues` and `Trie` variants of `GetRequest` should be disabled by default (via appropriate config settings)
* [ ] `completed_blocks` vs `complete_blocks` - use consistent naming (across the node, not only binary port)
* [x] Each request that take a block as an input should use `BlockIdentifier` and not be limited to either `BlockHeight` or `BlockHash`
* [x] Add a `Status` request that will deliver all data needed for the `/status` endpoint at once
* [x] NCTL, casper-test **and** casper-client-rs should talk to sidecar in the initial release - then we can consider modifying them to talk directly to the binary port
* [x] Rework `TrySpeculativeExec` and `TrySpeculativeExec` - speculative execution should require only a single call to `TrySpeculativeExec` (unlike right now, when it first needs to do `TrySpeculativeExec`. 
* [x] Create new "upgrade scenario" to test upgrade from a node without sidecar
* [x] Create test that verifies that RPC sidecar is able to process legacy data (pre 1.5)
* [x] BinaryRequest two-pass parse
* [ ] Proptest for `TryAcceptTransaction` and `TrySpeculativeExecution`
* [x] Write binary protocol specification
* [x] bytesrepr roundrip tests
* [x] component tests for `Db`, `TrySepculativeExec` and `TryAcceptTransaction`