[FEATURE] Create employee directory only accessible to admins

[kaiyangzheng]

Acceptance Criteria

• There is a new page accessible through the dashboard sidebar containing a list of employees
• The new page matches the design in figma: https://www.figma.com/design/xTNJRHyohsIf714Ba1eWFY/Hi-fi-Wireframes?node-id=5762-3297&m=dev
• Only admins can access the page through the dashboard sidebar and the route the page is served through
• Admins can edit employee information on the page (name, email, position, department)
• Admins can delete employees on the page

Note: backend guards will not be in the scope of this ticket, there will be other tickets that implement role restricted routes