Changes to allow the font subsystem to be built without enabling the entire graphics system (CONFIG_NX).  Adds CONFIG_NXFONTS and CONFIG_NXGLIB.  NX and NXFONTS are still pretty heavily entangled

Squashed commit of the following:

    libnx: Need to duplicate some Kconfig setting for NXFONTs if it can be configured and built independently of NX.  Also includes some build-related fixes.

    configs/sim:  Disable NX graphics support in the fb configuration.

    libnx:  Basic configuration and build changes to support building font support independend of the NX server.

    fs/userfs:  This completes coding of the UserFS client and of the UserFS feature in general.  This feature is being merged to main now because I believe it is innocuous.  It is, however, untesed.  The next step will be to develop a test case to verify the feature.
    fs/userfs:  Completes the request logic for the UserFS client.  Still need the logic that receives the responses.
    fs/userfs:  Completes coding for most of the server side of the user filesystem logic.
    fs/userfs:  Big design changes, simplications. Use Unix domain local sockets instead of message queues.  Easier to transfer big data in local sockets than message queues.  Remove character drvier 'factory' it is not necessary.
    fs/userfs:  Minor reparitioning; volume private info does not need to be held on the OS client side.
    libc/userfs:  Add some of the server side logic.
    fs/userfs:  Add some UserFS initialization logic.
    fs/userfs:  Add frame work for the UserFS proxy.  Remove all references to a block driver.  There is no block dricer... what was I thinking?
    fs/userfs: Add some initialization of the character driver, 'factory' device.
    fs/userfs:  Rename from fusefs to userfs to that we don't stomp on someone else's cool name.
    Add a header file describing the fusefs interface.

Add logic to support custom board directories that include a Kconfig file.  During the context phase of the build, any Kconfig file in the custom board directory is copied into configs/dummy, replacing the existing Kconfig file with the target Kconfig file.

Make system: Build the drivers/ directory even if file descriptors are disabled.  There are still things that may be needed from the drivers/ director (such as SYSLOG logic or lower half drivers).

boardctl(): Add a new non-standard OS interface.  This is similar to a driver IOCTL call.  But this is an IOCTL call directly on the board logic.  This function will eventually replace all of the ad hoc OS interfaces that are current used to perform application specific intialiation and application driver test confifuration.  It essentially formalizes and institutionalizes these rogue interface in to at least a single crazy call.