Genode: constrain osTryAllocPages to RAM quota (#6883)

Genode software components all start with an explicit RAM resource quota
which may or may not be upgraded during runtime by the parent process.
With this patch `osTryAllocPages` will fail if allocation exceeds quotas
set by the parent and the `osAllocPages` procedure will trigger a
blocking request to the parent to increase quotas. The previous behavior
could potentially block both procedures indefinitely for a quota upgrade
rather than fail and trigger garbage collection.

This patch also adds tracking of Genode dataspace mappings into the
component address space so they can be detached and freed.

lib/system/osalloc.nim

@@ -78,17 +78,7 @@ when defined(emscripten):
     munmap(mmapDescr.realPointer, mmapDescr.realSize)
 
 elif defined(genode):
-
-  proc osAllocPages(size: int): pointer {.
-   importcpp: "genodeEnv->rm().attach(genodeEnv->ram().alloc(@))".}
-
-  proc osTryAllocPages(size: int): pointer =
-    {.emit: """try {""".}
-    result = osAllocPages size
-    {.emit: """} catch (...) { }""".}
-
-  proc osDeallocPages(p: pointer, size: int) {.
-    importcpp: "genodeEnv->rm().detach(#)".}
+  include genodealloc # osAllocPages, osTryAllocPages, osDeallocPages
 
 elif defined(posix):
   const