aad3090 [rpc] Adding ::minRelayTxFee amount to getmempoolinfo and updating mempoolminfee help description (Jeff Rade)
Pull request description:
These are RPC document changes from #11475 which is now merged. Took into consideration comments from #11475 and #6941 for this PR.
Biggest change here is when calling `getmempoolinfo`, will now show the `minrelaytxfee` in the JSON reponse (see below):
```
$ bitcoin-cli getmempoolinfo
{
"size": 50,
"bytes": 13102,
"usage": 70480,
"maxmempool": 300000000,
"mempoolminfee": 0.00001000,
"minrelaytxfee": 0.00001000
}
```
Fixes#8953
Tree-SHA512: 5ca583961365ee1cfe6e0d19afb0b41d542e179efee3b3c5f3fcf7d3ebca9cc3eedfd1434a0da40c5eed84fba98b35646fda201e6e61c689b58bee9cbea44b9e
Almost all test scripts currently need to override the __init__()
method. When they do that they need to call into super().__init__() as
the base class does some generic initialization.
This commit makes the base class __init__() call into set_test_params()
method. Individual test cases can override set_test_params() to setup
their test parameters.
