add admin button to homepage and hamburger-menu

[trstngttschlk]

Description

• added Admin button to homepage linking to adminDashboard
  • used FaUserShield as logo for Admin button
• added Admin link to HamburgerNav linking to adminDashboard
• added Admin button testing to landing.cy.js and tgt.js

Type of change

Please select everything applicable. Please, do not delete any lines.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• This change requires an update to testing

Issue

• Is this related to a specific issue? If so, please specify:
  closes Create a button to access the admin dashboard #405

Checklist:

• This PR is up to date with the main branch, and merge conflicts have been resolved
• I have executed npm run test and all tests have passed successfully or I have included details within my PR on the failure.
• I have executed npm run lint and resolved any outstanding errors. Most issues can be solved by executing npm run format
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings

[Caleb-Cohen]

Howdy! Button looks great!

Everything looks good. One request. Can you add button testing to cypress/e2e/landing.cy.js?

I will want to merge this after we finish #439 so that users do not have access to the menu button.

[trstngttschlk]

Hi Caleb,
Added testing for the new admin button.
Please let me know if any changes are needed.
Thanks.