https://mainnet.decred.org/insight/api/ not exists

[lealife]

politeia/util/paywall.go

Lines 31 to 32 in dda9080

	insightMainnet = "https://mainnet.decred.org/insight/api"
	insightTestnet = "https://testnet.decred.org/insight/api"

https://mainnet.decred.org/insight/api/ not exists, the insight/ should be removed, the https://mainnet.decred.org/api/ is ok.
but the https://testnet.decred.org/insight/api/ is ok.

So the mainnet and testnet insight api is not the same, it's confused!

test cases:

• https://mainnet.decred.org/insight/api/addr/Dsggdniu5R3cakuNWv8hpaCRfQLeSEhuJ88 404
• https://mainnet.decred.org/api/addr/Dsggdniu5R3cakuNWv8hpaCRfQLeSEhuJ88 200
• https://testnet.decred.org/insight/api/addr/TsZJRxXFtdHHodwzYJqCaxprfqMYxDNx6sv/utxo 200
• https://testnet.decred.org/api/addr/TsZJRxXFtdHHodwzYJqCaxprfqMYxDNx6sv/utxo 404

[marcopeereboom]

We just need to remove all insight stuff.

[crypto-rizzo]

Working on this issue for the GUI side so I'll pick this up as well

[marcopeereboom]

@camus-code don't leave this hanging please.

[crypto-rizzo]

@marcopeereboom I pushed changes the day @lukebp asked for them. Just waiting for another review