GREG-82: Style tabs

Adding two buttons to a component that can be reused in the sponsor flow.

One links to the front page and the other to the registation page.

frontend/src/routes/components/sponsorGuestButtons.tsx

@@ -3,7 +3,7 @@ import { Box, IconButton, Theme } from '@mui/material'
 import PersonAddIcon from '@mui/icons-material/PersonAdd'
 import React from 'react'
 import { useTranslation } from 'react-i18next'
-import { useHistory } from 'react-router-dom'
+import { Link, useHistory } from 'react-router-dom'
 
 interface SponsorGuestButtonsProps {
   yourGuestsActive?: boolean,
@@ -16,7 +16,7 @@ export default function SponsorGuestButtons(props: SponsorGuestButtonsProps) {
   const history = useHistory()
 
   const goToOverview = () => {
-    history.push('/')
+    history.push('/sponsor')
   }
 
   const goToRegister = () => {
@@ -24,7 +24,7 @@ export default function SponsorGuestButtons(props: SponsorGuestButtonsProps) {
   }
 
   return (
-    <Box sx={{ display: 'flex', flexDirection: 'row', justifyContent: 'space-evenly' }}>
+    <Box sx={{ display: 'flex', flexDirection: 'row', justifyContent: 'space-evenly', marginBottom: '2rem' }}>
       <Box sx={{ display: 'flex', flexDirection: 'column', alignItems: 'center' }}>
         <IconButton onClick={goToOverview}>
           <PersonIcon