Update search input component to glimmer

[geneukum]

Let's update the SearchInput component to extend glimmer/component instead of ember/component. Glimmer components offer a bunch of various advantages over classic components and are the direction that ember is heading in general.

While we're here, let's prefer single quotes to double quotes throughout our template file, cleanup some test deprecations, and re-enable all of the ESLint rules for which this component was the only violator.

This should resolve the app/components/search-input.js section of https://github.com/ember-learn/ember-api-docs/issues/805.