Move projects listbox component to vue_shared

Problem statement

This is a technical debt issue. As part of the effort to deliver Create a Workspace from Gitlab UI (#385142 - closed), we implemented a listbox component to search and select a single project. We implemented it because we didn’t find a reusable component in the codebase.

We think that this component has the potential of being useful for other product groups therefore we want to convert it into a reusable component.

Implementation guide

Follow these high-level instructions to complete this technical debt issue:

1. Move the search_projects_listbox.vue component to vue_shared/components/search_projects_listbox directory.
2. Move the search_projects.query.graphql located inside remote_development/graphql to a graphql directory inside the search_projects_listbox directory.
3. Move search_projects_listbox.vue test files following the directory structure described in step 1.
4. Update all the components that reference search_projects_listbox.vue.
5. Create a Storybook story for the component. You can use the following story file as a reference: https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/app/assets/javascripts/remote_development/pages/list.stories.js.