Using i18next's "nesting" and "interpolation" features should reduce the
overall number of strings to translate, as well as provide a
standardized pattern for shortcut tooltips (if applicable).
Note that this approach is still allowing for flexibility regarding
differently structured sentences in each language.
Resolves#315
Press 'S' to show the Strava buttons (if the API key has been set) as
well as the Strava segments layer (once it has been fetched).
Note that fetching and updating data from Strava still needs to be
triggered manually by clicking the respective biking or running button.
