Change Details

* rpc: Use IsValidNumArgs over hardcoded size checks * rpc: Uncouple rpcs from maxTxFee global * doc: Add release notes for 15620 This is a backport of Core PR15620

* rpc: Use IsValidNumArgs over hardcoded size checks * rpc: Uncouple rpcs from maxTxFee global * doc: Add release notes for 15620 This is a backport of Core [[https://github.com/bitcoin/bitcoin/pull/15620 | PR15620]]

* rpc: Use IsValidNumArgs over hardcoded size checks * rpc: Uncouple rpcs from maxTxFee global * doc: Add release notes for 15620 This is a backport of Core [[https://github.com/bitcoin/bitcoin/pull/15620 | PR15620]]