GitHub Issue #11 cleanup code repo

[lhridley]

Summary

Modifies the code repository for easier management and maintenance of the project using Composer as the package management toolset:

• Removes the /vendor directory from the project
• Removes docroot/core, and docroot/modules/contrib from the project
• Adds /vendor, /docroot/core, /docroot/modules/contrib, /docroot/themes/contrib to the .gitignore file

Metadata

Question	Answer
Did you use a meaningful pull request title?	yes
Did you apply meaningful labels to the pull request?	no, I'm not sure what this means
Did you perform a self review first?	yes
Documentation reflects changes?	yes
CHANGELOG reflects changes?	no, the CHANGELOG does not appear to currently be in use
Unit/Functional tests reflect changes?	no, this is not applicable
Did you perform browser testing?	yes
Risk level	Medium -- may require modifying build scripting to execute composer install

[RCheesley]

Thanks for getting started on this @lhridley, hopefully with the other PRs we should be able to get this merged and start moving on the actual development work