Changed the way the lsblk output is generated so it can be modified with regular expressions to exclude empty read-write loop devices and strip it down to only the RO output.

The piping introduced and issue that prevented the `if` from picking up the return value of lsblk.

Moved the piping out of the if-statement.

Fixed some user errors I made in the last commit.
Put variables in quotes so newlines/line breaks are retained.

- Reworked solution to be easier to understand, simpler and more efficient.
- Corrected spelling
- Added detailed documentation of every step
- Split every step into their own line
- Added simplified explanation of the RegEx