Guidelines for users/contributors

[MatthewFlamm]

Add guidelines for third parties somewhere, for example README, CONTRIBUTING.MD, or the documentation. For reference the guidelines from openjournals/joss-reviews#5749 are:

Community guidelines
There should be clear guidelines for third-parties wishing to:

Contribute to the software
Report issues or problems with the software
Seek support

There are already some guidelines around running the content in the Tutorials, and issues related to that are already covered by #3 and #5 . When those are addressed, adding in detail to the existing content explaining how to setup the environment for and run the Tutorials would be also be useful for users.

[mendezVKI]

We added a contribuing.md file with instruction for contributing