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.
This allows the end user to use the {.magic: "IntDefine"/"StrDefine"}
pragmas to pass values into code at compile time. This has a nice side
effect of also allowing/requiring a default value to be assigned in the
code (see osalloc.nim/StandaloneHeapSize for an example)
