Improve UI

[treiher]

• Enable renaming of entities on entity page (e.g., renaming of exercise on exercise page instead of exercises page)
• Add interval button for showing all values in chart
• Show interval bounds above chart
• Warn about unsaved changes before switching page (in particular on workout page) (example)
• Warn about unsaved changes when using back button of device
• Prevent creation of routines or exercises with names containing leading or trailing spaces
• Use cumulative values per week on workouts page
• Add list of sets to exercise page
• Improve layout of training session summary (similar layout to list on exercise page)