This PR serves as my working changes to 5.2 before release.

• traceLast is deceiving, as if there is time between the last emission and completion that time is counted. Name it traceUntilComplete instead.
• traceWhile was just an opposite of traceUntil which doesn't do it's name justice. I've since super charged it, traceWhile will trace starting with an emission that passes the test and ending with the first failure. It will also produce multiple traces, e.g, of(false, true, false, true, true, false).pipe(traceWhile('while', a => a)) will produce traces for the time between the 2nd and 3rd emission and the 4th and 6th emissions. Imagine it's use in a game loop: traceWhile('timePlaying', state => state.isPlaying && !state.isGameOver)
• Added orComplete options to traceUntil and traceWhile
• Needed carets on the versions ^^^^^^^^^^!
• Collection doc path should be optional
• traceComplete has to be after first as isStable itself is not completing
• AngularFirePerformance was not eagerly initializing performance monitoring
• Ack, my performance operators weren't lazy! Fixed
• Inject the default app into AngularFirePerformance
• Dropped the Angular 8.0-rc from package.json as it's released now
• Moving all the deps from the schematic to peer and adding them during the ng add step
• Making the ng add more forgiving if they already have a .firebaserc or firebase.json
• Added ng7 and ng8 build tests
• Dropped unneeded stuff from the ngmodule package.json bringing them back inline with APF, though should update to AFP v8
• Indicate side effects so webpack doesn't wreak us
• Making AngularFirePerformance lazy and replacing dynamic import with empty() in the UMD
• Replacing dynamic import of firebase/messaging with empty() in the UMD, fixes AngularFireMessaging keeps Universal from compiling #1938