Makes lots of changes to RL8 installation script - restructuring, improvements, fixes

This commit makes lots of changes to the RL8 installation script, based partly on runs on segments-rl8, but also some based on philosophy (separating installation of packages (run_block_2), configuration of software (run_block_3), and starting Apache and MariaDB (run_block_4), to help isolate issues). Some changes are noted in the server issue - "Create, test, and update RL8 installation script" - #26 .