fix: Ensure both Controller and LabbcatImp agree on how to get DB connection parameters.
refactor: Move servlet-container-specific dependencies into controller.jsp, so Controller class is container version agnostic.
chore: Tidy installer script.
refactor: Get installer working with fewer Tomcat9 dependencies.
refector: Remove dependencies on javax.servlet from LabbcatImp and all upgraders.
chore: Remove all javax.servlet.* dependencies from nzilbb.labbcat.server (dependencies remain in legacy codebase)
chore: Run upgrades ostensibly in an Upgrader thread, so the new upgrade UI can follow progress
chore: Remove all javax.servlet.* dependencies from nzilbb.labbcat.server (dependencies remain in legacy codebase)