Change - Metadata field selector, add infinite scroll for data paginated

[VictorHugoDuranS]

Hi @tdonohue , I'm @jtimal partner, I like to share this PR with you:

References

• Fixes #2730

Description

I changed metadata field selector add infinite scroll for pagination all data from metadata field service, this change load all options in the start

Instructions for Reviewers

To see the new implementation, I attch a video with the functionality: https://youtu.be/8D-EjhubABI

List of changes in this PR:

• I changed the template metadata-field-selector.component.html adding the infinite scroll directives
• I changed the search function to page the query detecting change value on input
• I changed the observable list to "behaviorsubject" for update the current list
• I added a function for update the current list options according the query search, only if the user scroll to last item of the list

Checklist

• [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.
• [x] 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.
• [x] If my PR fixes an issue ticket, I've linked them together.