Allow the server to auto-configure the server URL for the client (#649)

* Allow the server to auto-configure the server URL for the client

* Extract server URL/version logic out to ensure consistent updates

* ()

* Be more explicit about when the server version is re-fetched

* Use a single layer of context provider

* Move the bootstrap route to /account/needs-bootstrap

* No more `isActual`

* Refactor to call subscribe-needs-bootstrap instead of fetch()

* Dedupe calls to subscribe-needs-bootstrap

* Don’t revalidate the server when we just validated it

* simplify

* Fix setServerURL