Update mounted check to support symlink paths

[jrmycanady]

Description

This change modifies the mounted check to resolve any symlinks so the grep on /proc/mounts will find any mounted devices.

Issues Resolved

#129 - filesystem tries to run mkfs every time when /dev/disk/by-id device path is used

Check List

• [x] A summary of changes made is included in the CHANGELOG under ## Unreleased
• [ ] New functionality includes testing.
• [ ] New functionality has been documented in the README if applicable.