Fixes #50: Improve organization of “chart gallery”

[maggiejaenicke]

Changes made:

• Adds carousels for quarterly river conditions and monthly flow tiles.

  • I decided to add river conditions videos directly into the site for a few reasons. The drupal link seems to error a lot, and I think maybe we consider replacing that slide click trigger (handleSlickClick() function on line 57 of RiverConditions_Carousel.vue) to drupal to go to twitter instead (or removing it altogether and just having the videos as they are in the site). When I had the carousel as just images, I could not get the thumbnails to stop opening in full screen without disabling full screen for other elements throughout the app which is why I pivoted to embedded videos.

Testing:

Before making this pull request, I:

• [ ] Cleaned the code the way Vue likes it - run 'npm run lint --fix'
• [ ] Made sure all tests run
• [ ] Ran WAVE plugin 508 compliance tool

I can confirm this has been checked on:

• [X] Chrome
• [ ] Safari
• [X] Edge
• [ ] Firefox
• [ ] Samsung Internet
• [ ] Internet Explorer 11 (not supported, but still needs at least a working user redirect page)

[maggiejaenicke]

@cnell-usgs Made a few changes and opened issues based on your comments, so it should be good to merge in! I can't merge it myself because of my permissions on this repo.