refs TryGhost/Product#3743
- Users should be able to hide the free plan from Portal, which removes it as an option on the main portal /signup page
- However, they should still be able to use the /signup/free link to allow members to signup for the free plan. Currently if the free plan is hidden from portal, the /signup/free link renders the main /signup page, with only paid plans available.
- This PR fixes that by allowing the /signup/free link to work even if the free plan is hidden from portal, but only by directly accessing the /signup/free link
refs https://github.com/TryGhost/DevOps/issues/50
- `react-app` comes from `eslint-config-react-app`, which is a CRA package
- we're moving away from that so this commit switches the linting over
to a more recently updated plugin
- once that was removed, we started using a newer version of
`@typescript-eslint/eslint-plugin`, so there were plenty of
updates/exemptions to make