dbus-vis: Initial commit

dbus-vis visualizes PCAP files captured by busctl as well as
text-format outputs from busctl.

dbus-vis displays the visualized results in horizontal
timelines, where each horizontal bar represents a DBus request, or
an IPMI request (an IPMI request is a specific kind of DBus request
sent to the IPMI daemon.)
The requests may be grouped by one or more fields including
type, sender, destination, path, interface, member.

In addition, if the BMC console is available, dbus-vis can connect
to the BMC console and capture DBus/IPMI requests in real time.

dbus-vis is in the form of a web page and is wrapped using Electron
to run as a desktop app.

Basic usage:
* Mouse click and drag:
  * If mouse is over time axis: drag timeline horizontally
  * If mouse is over vertical scroll bar: scroll up/down
  * Otherwise: select a region for measuring time & zooming in
* Mouse Scroll wheel:
  * If mouse is over time axis: zoom in/out
  * Otherwise: scroll up/down
* Click on the expandable headers will expand/collapse the entries under
that particular header.

Signed-off-by: Sui Chen <suichen@google.com>
Change-Id: I863c2ba80025d10efb44fd12868e37912fae9a47
diff --git a/dbus-vis/.gitignore b/dbus-vis/.gitignore
new file mode 100644
index 0000000..ea555fa
--- /dev/null
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+node_modules
+*.js~
+dbus-pcap~
+*.tar.gz