Harvest UI tweaks

Following a user demo, users expressed that the Harvest UI needed some adjustments

Changes

Fixes bugs in folder grid alignment
Drop down chevrons are now not shown if there is no expandable content
Mappings are now inherited from their parent folders
Root mapping button is now not shown if there are no Harvest items directly underneath it
Changes terminology for a few UI elements
- "Change mappings and UTC offset" is now "Add mappings and UTC offset"
- Adds sidebar tip "You don't have to change anything for files that have no problems"
Adds action buttons / hyperlinks to action on tips in sidebar
Adds an extra tip to differentiate between duplicate files in the current upload and previous uploads
Shows the site ID in a tooltip for mappings when the user hovers over
UTC offset now shows relevant offsets to the site location at the top of the dropdown box
Creates tests for folder row component
Creates tests for file row component
Creates tests for UTC offset component
Adds tests to metadata review component to ensure mappings are inherited correctly
Updates dependency @angular-devkit/build-angular
Removes deprecated usage of ~ in scss imports
Modified association decorator to not always use cached model. It now checks that the cached model has the same id as the requested model before returning the cached model. If the two id's do not match, the model is fetched from the API, and the cached model is updated (Currently failing tests)