Add ESL theme

[wwelling]

References

Resolves #5

Description

There are a lot of extraneous comments that came along with overriding core dspace-angular components and modules. We will be attempting minimal changes to files copied for overriding to afford easier synchronization when merging from upstream.

Reimplements ESL theme by customizing simple and full item view with link to Energy Systems Laboratory home page.

Instructions for Reviewers

Following instructions described in https://github.com/TAMULib/DSpace/issues/198 and switching out with community and collections under Energy Systems Laboratory.

List of changes in this PR:

• Add esl theme under the DSpace 7 theming guidelines.
• Customize UntypedItemComponent for simple item view.
• Customize FullItemPageComponent for full item view.

Checklist

This checklist provides a reminder of what we are going to look for when reviewing your PR. You need not complete this checklist prior to creating your PR (draft PRs are always welcome). If you are unsure about an item in the checklist, don't hesitate to ask. We're here to help!

• [x] My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• [x] My PR passes ESLint validation using yarn lint
• [x] My PR doesn't introduce circular dependencies (verified via yarn check-circ-deps)
• [ ] My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• [ ] My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• [ ] If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• [ ] If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• [ ] If my PR fixes an issue ticket, I've linked them together.

[kaladay]

I'll just note that from the discussion we had my understanding is that the code comments that represent commented out code are from the original base theme. These are copied as-is to keep the difference between the original code as small as possible and less likely to have a merge conflict.