Add test priorities, and select proper table to fill

Associate priorities with some tests in order to select the most favored
result whenever more than one test result occurs for a sample
point/analyte pair. Fill appropriate db table (MajorChemistry or
MinorandTraceChemistry) based on analyte.
Fix analyte string for "Lead"
Switch from log4j2 to logback
Add tests of levels against quality standards
Convert to using sbt launcher

launcher.config file is in src/main/resources; not where it really belongs.