moves the loading icon into a component

opentech/static_src/src/app/src/components/Listing/index.js

...tech/static_src/src/app/src/components/Listing/style.scss

...h/static_src/src/app/src/components/LoadingPanel/index.js

...tatic_src/src/app/src/components/LoadingPanel/styles.scss

...tic_src/src/app/src/components/SubmissionDisplay/index.js

...static_src/src/app/src/containers/DisplayPanel/style.scss

opentech/static_src/src/sass/apply/abstracts/_mixins.scss

opentech/static_src/src/sass/apply/abstracts/_variables.scss