URL redirect to support default Pleroma URLs when static-fe is not enabled in Pleroma, fixes #39, #61, #64, #68, #69 and #81

Addresses the following 5 issues: https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/39 https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/61 https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/64 https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/68 https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/69 https://gitlab.com/soapbox-pub/soapbox-fe/-/issues/81