netmap: EigenTrustAlpha config encoding diverges from the protocol

[cthulhu-rider]

Is your feature request related to a problem? Please describe.

• API
• code

Describe the solution you'd like

backport changes to API docs

Describe alternatives you've considered

harder way:

• follow current protocol and fix encoding
• fix config in the running networks

Additional context

Client testing

[roman-khimov]

I think our networks are all configured with string-based values and I'd also check for reader code, probably it works with text-based ones as well. Overall I'd expect for API to win here.

[cthulhu-rider]

func TestEigenTrustAlpha(t *testing.T) {
	m := &protonetmap.NetworkInfo{
		NetworkConfig: &protonetmap.NetworkConfig{
			Parameters: []*protonetmap.NetworkConfig_Parameter{
				{
					Key:   []byte("EigenTrustAlpha"),
					Value: []byte("0.123"),
				},
			},
		},
	}
	b, err := proto.Marshal(m)
	require.NoError(t, err)
	var n netmap.NetworkInfo
	require.NoError(t, n.Unmarshal(b))
	require.EqualValues(t, 0.123, n.EigenTrustAlpha())
}

=== RUN   TestEigenTrustAlpha
    network_info_test.go:524: 
        	Error Trace:	/home/ll/projects/neofs/sdk/netmap/network_info_test.go:524
        	Error:      	Not equal: 
        	            	expected: 0.123
        	            	actual  : 1.08637830059e-312
        	Test:       	TestIk
--- FAIL: TestIk (0.00s)

---

$ neo-go contract testinvokefunction -r https://rpc1.morph.fs.neo.org:40341 7c5bdb23e36cc7cce95bf42f3ab9e452c2501df1 config string:EigenTrustAlpha
{
  "state": "HALT",
  "gasconsumed": "2849820",
  "script": "DA9FaWdlblRydXN0QWxwaGERwB8MBmNvbmZpZwwU8R1QwlLkuTov9FvpzMds4yPbW3xBYn1bUg==",
  "stack": [
    {
      "type": "ByteString",
      "value": "MC4x"
    }
  ],
  "exception": null,
  "notifications": []
}

which is 0.1

[roman-khimov]

https://github.com/nspcc-dev/neofs-node/blob/3129bdeadc87017c95d4877b82c57e64db5539f8/pkg/morph/client/netmap/config.go#L106-L113
I think it's only SDK that does it wrong.

[cthulhu-rider]

$ neofs-cli netmap netinfo -r grpcs://st1.storage.fs.neo.org:8082
Epoch: 28043
Network magic: [net 0x572dfa5] 91414437
Time per block: 15s
NeoFS network configuration (system)
  Audit fee: 50000000
  Storage price: 100000
  Container fee: 1000000000
  Container alias fee: 200
  EigenTrust alpha: 0.1
  Number of EigenTrust iterations: 4
  Epoch duration: 240
  Inner Ring candidate fee: 10000000000
  Maximum object size: 67108864
  Withdrawal fee: 100000000
  Homomorphic hashing disabled: false
  Maintenance mode allowed: true
NeoFS network configuration (other)

interpretation is OK, incorrectly transmitted