Add coverity push script

[paul-elliott-arm]

Description

This is the script to allow us to push coverity builds from Jenkins (or anyone's machine come to that)

Functionality is documented within the script, but to test:

either:

export COVERITY_TOKEN=token
path/to/mbedtls/scripts/push_coverity_scan.py path/to/mbedtls -b origin/coverity_scan -e email@arm.com

or

path/to/mbedtls/scripts/push_coverity_scan.py path/to/mbedtls -t token -b origin/coverity_scan -e email@arm.com

The token can be found from the coverity web interface, and for the email address I would use your own email address for now (email address is unfortunately compulsary). Conversations are ongoing about which address to use for notifications in the future, the notification email will look like this:

 Your request for analysis of ARMmbed/mbedtls has been completed successfully.
    The results are available at <url>

    Build ID: 607763

    Analysis Summary:
       New defects found: 0
       Defects eliminated: 0

Should new defects be found, another email will be generated, but this will go to the whole team (this is specified within coverity itself)

WARNING - the mbedtls directory specified will be switched to the latest version of the branch specified, any outstanding differences will cause the script to fail.

PR checklist

Please tick as appropriate and edit the reasons (e.g.: "backport: not needed because this is a new feature")

• changelog provided, or not required (script for CI and maintainers only)
• 3.6 backport done, or not required (Script will only basically be run on development)
• 2.28 backport done, or not required (Script will only basically be run on development)
• tests provided, or not required (CI script, CI runs will be tested, but other than that we can't test.)

[gilles-peskine-arm]

We're going to run this script at least on both tf-psa-crypto and mbedtls, and possibly on LTS branches. So it belongs in mbedtls-test or mbedtls-framework. Probably mbedtls-test since this isn't something we normally run manually?

[paul-elliott-arm]

I was in discussion with Bence about whether or not this belonged in mbedtls-test anyway. Given it won't pass on Ubuntu16.04, I think that its probably a good idea to move it there, but need to have a quick word with Bence first (he's not in today)

[paul-elliott-arm]

Closing, as moving to mbedtls-test here