Refactor shiny integration for series, sampling, group and individual metrics

[cedricbriandgithub]

TODO list when receiving new datacall

• [ ] run db change on the server
• [ ] copy script to server
• [x] check that column names listed in loading_functions correspond to columns generated in the template (same order)
• [x] test integration new sampling
• [ ] test update sampling
• [ ] re-test new group metrics series
• [x] test new group metrics sampling
• [ ] re-test updated group metrics series
• [ ] test updated group metrics sampling
• [ ] re-test deleted group metrics series
• [ ] test deleted group metrics sampling
• [ ] re-test new individual metrics series
• [x] test new individual metrics sampling
• [ ] re-test updated individual metrics series
• [ ] test updated individual metrics sampling
• [ ] re-test deleted individual metrics series
• [ ] test deleted individual metrics sampling