Theme switching

[Brian-Clement]

Description

Re-enables the old Hatter theme and sets it as the site default. Introduces the Switch Page Theme module to leave the green "O'MidCamp" theme enabled on/2020* pages only.

To test

• (Optional) Build locally
  • Install dependencies with composer install
  • Import configuration with drush cim -y
  • Follow the test instructions below with your local (using midcamp.org.docker.amazee.io URL)
• Visit the homepage (https://nginx.feature-theme-switching.midcamp-org.us2.amazee.io/) and observe the old theme is enabled.
• Visit 2021 event year pages like /2021/news or /2021/about. Observe the old theme is enabled.
• Visit 2020 event year pages like /2020/organizers or /2020/about. Observe the green theme is enabled.

[backlineint]

Short term, I think this is fine to get the site back to our default colors. But going back to the original hatter theme will lose out on some changes that were made to the hatter base theme (that the O'midcamp theme depended on.) Templates for the caption field and some webform related theming look to be the biggest changes.

We could port those back to the original hatter theme, but my preference would be to create a new evergreen theme that uses hatter_base and an updated version of hatter_v2 style guide that is reverted back to our default theme.

Merging what we have now will give me a little more time to work on that, and when that is ready the only real config change we'll need to make would be changing the default theme setting.

[backlineint]

Created a WIP PR for the Hatter changes here: MidCamp/hatter-v2#19

[Brian-Clement]

We could port those back to the original hatter theme, but my preference would be to create a new evergreen theme that uses hatter_base and and updated version of hatter_v2 style guide that is reverted back to our default theme.

This sounds ideal @backlineint. I feel the approach in this PR should only be considered a stop-gap measure. I will merge this for now and be ready to move to the new theme once it is ready.