refactor: cleans up speaker pagination into separate component

[dominikeinkemmer]

References https://github.com/WWCodeTokyo/speak-her-db/issues/180

Proposed Changes

Description of changes in this PR

• Refactors speaker pagination into it's own component to follow the DRY principle.
• Changes the naming of lastPage to lastEntry for consistency

Testing Plan

How do the reviewers QA this? Feel free to write unit tests or describe manual testing steps here

• Load the start page
• Try to paginate

Note: There will be no visible changes on the frontend after this change.

[tuttiq]

Ughhh this ESLint check still doesn't work 😞 I'll just go ahead and merge anyways...