The goal of this commit is to add the equivalent to gdbinit but
for lldb. I've tried to replicate the commands as close as possible
but I'm unsure about the jss command and hoping to get some feedback
on it in addition to the bta command which I'm not sure how/when this
could be used. This is probably just inexperience on my part.

The lldbinit file can be placed into a directory prefixed with dot
(.lldbinit) and the python script is currently expected to be in the
same directory. The path to the script can be changed manually if needed
as well.

NOTRY=true

Review-Url: https://codereview.chromium.org/2758373002
Cr-Commit-Position: refs/heads/master@{#44136}