Bug 1090689 - Add MPL2.0 headers to the repo

This work fixes part2 of Bugzilla bug [1090689](https://bugzilla.mozilla.org/show_bug.cgi?id=1090689).

This adds MPL2.0 headers to all the relevant files in the treeherder-service repo. The main file types receiving headers are:

* .py
* .pp
* .conf
* .sh
* .yml

Puppet config files can apparently use either `\* blockquote *\` or `# blockquote`, I chose the latter since there were existing single line `#` comments in some of those files.

All files were added via a list agreed on in the bug with @edmorley, and the .py injected en masse. Other files like .yml and the Vagrant file were manually added. Executables were reordered with their command interpreter invocation above the MPL block.

All init, .json, .rst docs and .txt files have been ignored. I had a look at a few of them to check. The odd file like `tests/log_parser/conftest.py` have been injected, even though they are empty at this time.

I don't have access to vagrant at the moment, so probably a good idea for someone to try this branch locally and make sure there are no errors on start up, before merge.

Sorry there are a lot of files :)

Adding @maurodoglio for review and @edmorley for visibility.