After addition of an improved Alice-API we no longer need
this workaround to filter data in the frontend.
When a view of all routes of a selected IXP participant
(possibly with multiple routers) is desired this should
become a new page (with assorted API extensions).
This reverts commit 15e728da2c6855a3fad6a22a58dbd6d62456a7cb.
In case of multiple peering routers of one customer, their
announcements are aggregated in a single per-customer table.
RoutesPage used to display contents of that table irrespectively
of the current router selected in the UI.
Now, when selecting a router in the UI RoutesPage is initialized
with the nextHop IP of that router to display only routes
(filtered, accepted and noexport) from that router.