Get fork information from getblockchaininfo instead of manually configuring

[hsjoberg]

The config should set the fork key from getblockchaininfo and then the rest can automatically set up:

{
	"result": {
		"chain": "main",
		"blocks": 681524,
		"headers": 681524,
		"bestblockhash": "00000000000000000003f11f7ea1501c799a09530dd3c751665a5ac7818b8657",
		"difficulty": 20608845737768.16,
		"mediantime": 1619951663,
		"verificationprogress": 0.9999929291006103,
		"initialblockdownload": false,
		"chainwork": "00000000000000000000000000000000000000001cce4dd390f48bb3db350888",
		"size_on_disk": 388722795567,
		"pruned": false,
		"softforks": {
			"bip34": {
				"type": "buried",
				"active": true,
				"height": 227931
			},
			"bip66": {
				"type": "buried",
				"active": true,
				"height": 363725
			},
			"bip65": {
				"type": "buried",
				"active": true,
				"height": 388381
			},
			"csv": {
				"type": "buried",
				"active": true,
				"height": 419328
			},
			"segwit": {
				"type": "buried",
				"active": true,
				"height": 481824
			},
			"taproot": {
				"type": "bip9",
				"bip9": {
					"status": "started",
					"bit": 2,
					"start_time": 1619222400,
					"timeout": 1628640000,
					"since": 681408,
					"statistics": {
						"period": 2016,
						"threshold": 1815,
						"elapsed": 117,
						"count": 2,
						"possible": true
					},
					"min_activation_height": 709632
				},
				"active": false
			}
		},
		"warnings": ""
	},
	"error": null,
	"id": null
}