Expose "bounce impact" and Storage Server "version catch-up rate" metrics

Changes:

Schemas.cpp: Extend the JSON schema to report the new metrics that have
been added.

mr-status-json-schemas.rst.inc: Update the schema to reflect the changes
made to the JSON schema.

release-notes-700.rst: Add a note about the new metrics in "Status"
section.

documentation/sphinx/source/mr-status-json-schemas.rst.inc

@@ -121,6 +121,16 @@
                      "counter":0,
                      "roughness":0.0
                   },
+                  "fetched_versions":{
+                     "hz":0.0,
+                     "counter":0,
+                     "roughness":0.0
+                  },
+                  "fetch_frequency":{
+                     "hz":0.0,
+                     "counter":0,
+                     "roughness":0.0
+                  },
                   "grv_latency_statistics":{ // GRV Latency metrics are grouped according to priority (currently batch or default).
                      "default":{
                          "count":0,

documentation/sphinx/source/release-notes/release-notes-700.rst

@@ -32,6 +32,8 @@ Status
 ------
 * Added ``commit_batching_window_size`` to the proxy roles section of status to record statistics about commit batching window size on each proxy. `(PR #4735) <https://github.com/apple/foundationdb/pull/4735>`_
 * Added ``cluster.bounce_impact`` section to status to report if there will be any extra effects when bouncing the cluster, and if so, the reason for those effects. `(PR #4770) <https://github.com/apple/foundationdb/pull/4770>`_
+* Added ``fetched_versions`` to the storage metrics section of status to report how fast a storage server is catching up in versions. `(PR #4770) <https://github.com/apple/foundationdb/pull/4770>`_
+* Added ``fetch_frequency`` to the storage metrics section of status to report the version fetching frequency of a storage server. `(PR #4770) <https://github.com/apple/foundationdb/pull/4770>`_
 
 Bindings
 --------

fdbclient/Schemas.cpp

@@ -144,6 +144,16 @@ const KeyRef JSONSchemas::statusSchema = LiteralStringRef(R"statusSchema(
                      "counter":0,
                      "roughness":0.0
                   },
+                  "fetched_versions":{
+                     "hz":0.0,
+                     "counter":0,
+                     "roughness":0.0
+                  },
+                  "fetch_frequency":{
+                     "hz":0.0,
+                     "counter":0,
+                     "roughness":0.0
+                  },
                   "grv_latency_statistics":{
                      "default":{
                         "count":0,