The "someone dropped the mic" page that appears when a 404 or other error is being shown links to "go back" and "contact support" pages; but there are two problems here:

• if this is the first page you see on RHDH startup, 'go back' is meaningless
• if you've customized your RHDH instance then linking to a generic support page at https://github.com/backstage/backstage/issues is probably NOT what you want as a customer

So we need to:

• remove the 'go back' if there's no browser history to return to, and
• default the support link to something like https://access.redhat.com/support/policy/updates/developerhub or wherever we sed people to report RHDH bugs.