Added POST /eth/v1/beacon/blocks back in place

Mistakenly removed in ethereum#218, this PR puts back the /eth/v1/beacon/blocks POST.

apis/beacon/blocks/blocks.yaml

@@ -0,0 +1,52 @@
+post:
+  tags:
+    - Beacon
+    - ValidatorRequiredApi
+  summary: "Publish a signed block."
+  operationId: "publishBlock"
+  description: |
+    Instructs the beacon node to broadcast a newly signed beacon block to the beacon network,
+    to be included in the beacon chain. The beacon node is not required to validate the signed
+    `BeaconBlock`, and a successful response (20X) only indicates that the broadcast has been
+    successful. The beacon node is expected to integrate the new block into its state, and
+    therefore validate the block internally, however blocks which fail the validation are still
+    broadcast but a different status code is returned (202)
+  parameters:
+    - in: header
+      schema:
+        $ref: '../../../beacon-node-oapi.yaml#/components/schemas/ConsensusVersion'
+      required: false
+      name: Eth-Consensus-Version
+      description: "Version of the block being submitted, if using SSZ encoding."
+  requestBody:
+    description: "The `SignedBeaconBlock` object composed of `BeaconBlock` object (produced by beacon node) and validator signature."
+    required: true
+    content:
+      application/json:
+        schema:
+          oneOf:
+            - $ref: '../../../beacon-node-oapi.yaml#/components/schemas/SignedBeaconBlock'
+            - $ref: "../../../beacon-node-oapi.yaml#/components/schemas/Altair.SignedBeaconBlock"
+            - $ref: "../../../beacon-node-oapi.yaml#/components/schemas/Bellatrix.SignedBeaconBlock"
+      application/octet-stream:
+        schema:
+          description: "SSZ serialized block bytes. Use content type header to indicate that SSZ data is contained in the request body."
+  responses:
+    "200":
+      description: "The block was validated successfully and has been broadcast. It has also been integrated into the beacon node's database."
+    "202":
+      description: "The block failed validation, but was successfully broadcast anyway. It was not integrated into the beacon node's database."
+    "400":
+      description: "The `SignedBeaconBlock` object is invalid"
+      content:
+        application/json:
+          schema:
+            allOf:
+              - $ref: "../../../beacon-node-oapi.yaml#/components/schemas/ErrorMessage"
+              - example:
+                  code: 400
+                  message: "Invalid block: missing signature"
+    "500":
+      $ref: '../../../beacon-node-oapi.yaml#/components/responses/InternalError'
+    "503":
+      $ref: '../../../beacon-node-oapi.yaml#/components/responses/CurrentlySyncing'

beacon-node-oapi.yaml

@@ -80,6 +80,8 @@ paths:
     $ref: "./apis/beacon/blocks/header.yaml"
   /eth/v1/beacon/blinded_blocks:
     $ref: "./apis/beacon/blocks/blinded_blocks.yaml"
+    /eth/v1/beacon/blocks:
+      $ref: "./apis/beacon/blocks/blocks.yaml"
   /eth/v2/beacon/blocks/{block_id}:
     $ref: "./apis/beacon/blocks/block.v2.yaml"
   /eth/v1/beacon/blocks/{block_id}/root: