go: Add key manager worker status to node status

[peternose]

Task
Currently the key manager worker does not report any status as part of the GetStatus node control gRPC API call. It should provide some useful information about the operation of the key manager node.

Test
Tested locally using default fixture, simple-keymanager and minimal-runtime:

• Key manager status is shown only for keymanager nodes and not for compute, client and validator nodes.
• Status changes to ready once consensus is synced and key manager is registered.
• Client runtimes and access list populates with a short delay.
• Private peers are shown if we set them using the worker.keymanager.private_peer_pub_keys flag.

[codecov]

Codecov Report

Merging #4883 (fdaa307) into master (d0bb246) will increase coverage by 0.01%.
The diff coverage is 68.18%.

❗ Current head fdaa307 differs from pull request most recent head 8fc6860. Consider uploading reports for the commit 8fc6860 to get more accurate results

@@            Coverage Diff             @@
##           master    #4883      +/-   ##
==========================================
+ Coverage   66.54%   66.55%   +0.01%     
==========================================
  Files         452      454       +2     
  Lines       50418    50524     +106     
==========================================
+ Hits        33551    33627      +76     
- Misses      12705    12726      +21     
- Partials     4162     4171       +9     

Impacted Files	Coverage Δ
go/worker/keymanager/api/api.go	32.43% <32.43%> (ø)
go/control/control.go	71.42% <50.00%> (-1.08%)	⬇️
go/worker/keymanager/status.go	82.60% <82.60%> (ø)
go/oasis-node/cmd/node/control.go	65.45% <100.00%> (+1.30%)	⬆️
go/worker/keymanager/init.go	61.53% <100.00%> (+0.60%)	⬆️
go/worker/keymanager/worker.go	64.94% <100.00%> (+1.08%)	⬆️
go/common/sgx/common.go	66.01% <0.00%> (-3.89%)	⬇️
go/worker/common/committee/keymanager.go	88.33% <0.00%> (-3.34%)	⬇️
go/runtime/registry/host.go	69.38% <0.00%> (-2.86%)	⬇️
go/worker/keymanager/p2p/client.go	80.95% <0.00%> (-2.39%)	⬇️
... and 14 more

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[kostko]

One minor thing, otherwise looks good.

[kostko]

Also do squash the two commits as the second one actually fixes an issue introduced by the first one :)