chore: merge all of the work in the vue-app-cleanup branch to main

An extensive set of changes dealing with a number of client side bugs and enhancements. Full cleanup of the theme system. Removal of rubbish backup files. General refactoring. Added ESlint and prettier. Removed all hard coded fallback data. See included issues and scope of Milestone 17. Note that all of the changed in this MR have been cherry picked into the el-salvador branch.