FR: Extend `per_line_sub` feature to remediation

[jdrew82]

Environment

• hier_config: v2.2.0

Proposed Functionality

As a network automation engineer, I'd appreciate the ability to modify the remediation configuration lines.

Use Case

This is useful for situations where a negation line needs to be in a certain format for the network OS to accept it. For example, removing an SNMP user on Cisco Nexus requires the line to be truncated after the username and will error if the full line is presented.