Code review comment for ~samgilson/cloud-init:cloud-init-analyze-boot

Thank you for this branch Sam and for making cloud-init better!

A couple of notes:
 1. ^M characters present throughout:
    - cloudinit/analyze/tests/test_boot.py
    - doc/rtd/topics/analyze.rst

 2. Timestamps don't seem to be reported properly in an lxc container for me: (note that the kernel ended boot time abd cloud-init start time is in the future on my system:

root@x1:~# cloud-init analyze boot
-- Most Recent Boot Record --
   Kernel Started at: 2019-06-24 20:24:25.527606
   Kernel ended boot at: 2019-06-27 18:53:04.667329
   Kernel time to boot (seconds): 253719.139722
   Cloud-init start: 2019-06-27 18:53:05.277550
   Time between Kernel boot and Cloud-init start (seconds): 0.610222

root@x1:~# date
Mon Jun 24 20:39:25 UTC 2019

 2. timestamp reported by cloud-init boot doesn't match timestamp in cloud-init logs
  on my system. This may lead to confusing errors because you

 cloud-init analyze boot
   Cloud-init start: 2019-06-21 21:56:24.461153

YET cloud-init does startup @ 21.56:08

grep "running 'init-local" /var/log/cloud-init.log | tail -n 1
2019-06-21 21:56:09,067 - util.py[DEBUG]: Cloud-init v. 18.5-59-gb05832a5-1~bddeb running 'init-local' at Fri, 21 Jun 2019 21:56:08 +0000. Up 5.00 seconds.

Maybe we should be using ActiveEnterTimestampMonotonic or ExecMainStartTimestampMonotonic to represesent on cloud-init-local starts it's datasource discovery?

I'll continue to try to triage what might give us a better handle on cloud-init start time