Ground work for installing and upgrading database schema based upon DB provider (MySQL, PostgresSQL, SQL Server, etc.)
Cleaned up legacy cruft, refactored, commented and made simpler for to support additional database providers.
Two issues resolved relating to MySQL 8:
1. DB version checking skips MINOR/PATCH checks if MAJOR release changed.
2. Keyword 'admin' quoted to ensure MySQL compat.
Closes#152