context: scale max_quantum and add quantum_limit

Also scale the max_quantum with the selected rate. Add a new
quantum_limit property that is the upper limit of the quantum regardless
of the sample rate, this is usually the allocated buffer size.

See #1931

src/daemon/pipewire.conf.in

@@ -26,6 +26,7 @@ context.properties = {
     #default.clock.quantum       = 1024
     #default.clock.min-quantum   = 32
     #default.clock.max-quantum   = 8192
+    #default.clock.quantum-limit = 8192
     #default.video.width         = 640
     #default.video.height        = 480
     #default.video.rate.num      = 25