Analytics: update "language_change" Event to better represent users actions

[Dthurow]

What

Brief description of changes. Update the Google Analytics language_change event so it only triggers when the user first comes to the website, and every time they open the welcome popup and select a language. It used to be triggering every time someone would reload the page as well

Why

What problem does this pull requests solve? Reference related issues if appropriate. To fix issue #178, also related to #154

Ensure the following interactions work as expected. Please test using a mobile form factor.

• [x] Tapping on a marker on the map displays information about the marker in a popup.
• [x] Tapping the "Show list of locations" button replaces the map view with a list view.
• [x] Tapping an item in the list replaces the list view with a map view, and navigates the map to the tapped item on the map.
• [x] Tapping one of the ✅'s in the legend filters items on the map and in the list.
• [x] Changing the language to spanish changes things on the page.
• [x] Clicking the Help/Info button opens and closes a menu with information.
• [x] Clicking the X Close button on the Help/Info screen closes the modal.

Check the app in the following web browsers:

• [x] Chrome
• [x] Firefox
• [ ] Edge
• [ ] Safari

[Dthurow]

@amaxama Merged from master again and looks like all the tests have finished! Looks like I just need an approving review then I can have github auto squash and merge?