[PATCH] Add PBF reading support to JOSM

[taylor.smock]

This is a followup of #6886.

Major differences:

• It uses the JOSM Protobuf parsing code instead of Google's Protobuf parser
• It is not based off of any of the code from ​https://github.com/openstreetmap/OSM-binary except for the proto files. I'm unsure what the licensing situation would require.
• ~1500 added lines
• Performance for PBF reading when compared against the PBF plugin
  • ​colorado-latest.osm.pbf was used for profiling. Note: Takes ~8.8 GB of memory to load the file, no clue how much is needed to render it.
  • PBF plugin (max memory in use: 8779 MB):
    • Time spent loading PBF: 49.5s (3 runs with same time spent)
    • Memory allocations: 30,155,126,741 (average across three runs, ~500 MB spread)
    • CPU cyles: 3061 (average across 3 runs, ~600 CPU cycle spread)
  • Patch (max memory in use: 8783 MB):
    • Time spent loading PBF: 75s (average across 3 runs, min 62s, max 89s)
    • Memory allocations: 30,098,125,773 (average across three runs, ~900 MB spread)
    • CPU cyles: 4650 (average across 3 runs, min 3862, max 5356)