Could not find config for page

[andycate]

When I request a page with a name that doesn't exist, I get this error:

org.team5499.dashboard.ConfigException: Could not get configuration for page with name drive
        at org.team5499.dashboard.Config.getPageAttributes(Config.kt:129)
        at org.team5499.dashboard.Dashboard$start$2.handle(Dashboard.kt:89)
        at org.team5499.dashboard.Dashboard$start$2.handle(Dashboard.kt:24)
        at spark.RouteImpl$1.handle(RouteImpl.java:72)
        at spark.http.matching.Routes.execute(Routes.java:61)
        at spark.http.matching.MatcherFilter.doFilter(MatcherFilter.java:134)
        at spark.embeddedserver.jetty.JettyHandler.doHandle(JettyHandler.java:50)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1568)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
        at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:61)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
        at org.eclipse.jetty.server.Server.handle(Server.java:503)
        at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:364)
        at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260)
        at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
        at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
        at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
        at java.base/java.lang.Thread.run(Thread.java:834)

To Reproduce:
Run the Playground server, and navigate to a page name that doesn't exist in the config file

[andycate]

We might consider a different way of handling this error, like a 404 response.