Pierre-Eric Pelloux-Prayer authored Feb 26, 2021 and Tom Denis committed Mar 03, 2021

This commit introduces 2 features:
 - "umr --server url": starts a long running umr instance, accessible remotely
   It exposes a json based interface over a nanomsg transmission layer. See
   https://nanomsg.org/documentation.html.
 - "umr --gui [url]": a gui frontend. It can either connect to the GPU on the
   machine, or connect remotely to a "umr --server" instance.

   The features available from the GUI are (and their equivalent CLI switch):
     * --enumerate: to discover available GPUs and their config. Each GPU is accessible in its
     own tab.
     * --list-blocks: list IP blocks
     * --list-regs: list blocks registers. The registers can be filtered by name
     (a fuzzy search/match is used, so e.g. the filter "SDCNL" will match mmSDMA0_CNTL) or/and by
     bitfield names.
     * --vm-read/--vm-decode: read vmid or linear VRAM. When reading vmid memory the page table
     information will be displayed too.
     * --waves: dump waves. Waves information are parsed, so sgpr/vgpr are viewable (as int, uint,
     hex or float) and the shader disassembly is also available in the same view.
     * --ring: dump a given ring and display its disassembly.
     * --read: read a register and display its raw value and the individual bits. Register can also
     be auto-refreshed with a configurable frequency (default: 5 sec).
     * --write: update a register value, by modifing the raw 32 bits value or individual bits

Limitations:
  * mostly tested on Navi10
  * lacks most error checking in the GUI