Simplify approving hosts

The list of waiting hosts opens the approval dialog instead of having its
own name input and buttons, so hosts are approved in one place. Removes
the limit on requests per minute, the limits on pending requests already
cap what an address can do.

Also updates text that still said the installer makes the requests.

docs/devs/protocol.md

@@ -61,7 +61,7 @@ If a user token is sent and the user has the `core.host.approve` permission the
 An invalid token gives 401 and a user without the permission gives 403, a token is never ignored to create a pending request instead.
 
 A missing or too long name gives 400.
-Too many requests from the same address or in total gives 429 with a `Retry-After` header in seconds.
+Too many pending requests from the same address or in total gives 429 with a `Retry-After` header in seconds.
 
 ### `POST /api/host-pairing/poll`