Add rules for deprecated dropdowns

Part of #18 (closed) and #19 (closed)

Testing locally

1. Run a local scan
2. Visit http://localhost:3000/?search=check_id%20co%20%22bootstrap-dropdown-toggle-haml%22%20or%20check_id%20co%20%22bootstrap-dropdown-toggle-rb%22%20or%20check_id%20co%20%22bootstrap-dropdown-toggle-vue%22%20or%20check_id%20co%20%22dropdown-vue-component%22%20or%20check_id%20co%20%22vue-shared-dropdown-component%22%20or%20check_id%20co%20%22dropdowns-helper-haml-rb%22%20or%20check_id%20co%20%22okay-listbox-vue-component%22%20or%20check_id%20co%20%22okay-redirect-listbox-helper%22&groupBy=severity, which filters for all the new rules added here.

Screenshot