webapp/src/logo/asana.svg: Add Asana logo
webapp/src/logo/asana.svg: Add Asana logo

Following 5c83ad69 (src/logo/github.svg: Add a GitHub logo,
2016-11-20, #11).  This time the logo was from [1,2].  I converted
that to SVG using epstopdf v2.22 [3] and pdf2svg v0.2.1 [4]:

  $ epstopdf -o asana.pdf Logo-Vertical-Color.eps
  $ pdf2svg asana.pdf asana.svg

The EPS source had "asana" underneath the icon, and some clipPaths I
didn't understand.  I dropped paths from the SVG by hand until I got
down to just the small, dark logo.  Then I adjusted the width, height,
and viewBox on the svg element to remove surrounding whitespace while
keeping the viewport and viewBox square.

[1]: https://asana.com/styles
[2]: https://dl.dropboxusercontent.com/content_link/EheE2jpAtFMrUlFzZrpdTk10UxEVdMPFFNKpS7TX4B3whQiUChdF4pXUE1z04Pdr/file?dl=1
[3]: http://tug.org/epstopdf/
[4]: http://www.cityinthesky.co.uk/pdf2svg.html

Signed-off-by: W. Trevor King <f75897670c17327c42ab201733fb8a81ff9f4c34@tremily.us>

wking/depviz,jbenet/depviz,wking/depviz,jbenet/depviz