Add SVN deploy support to CircleCI config

[mindctrl]

Updates CircleCI config:

• Adds SVN deploy support. Deploys to trunk on master updates. Deploys new tagged version when a new git tag is created. Borrows from work done in other Genesis plugins.
• Updates prepare_environment command to install composer and WP and persists for other jobs in the pipeline.
• Adds composer_build job to install composer deps and persists to workspace for other jobs.
• Updates PHP executor to support 5.6, 7.2, 7.3, and 7.4 support for lints and phpunit tests.
• Adds npm_lint job to lint CSS and JS assets.
• Adds npm_build job to build CSS and JS assets.
• Adds bundle job to build a zip file if all tests pass.

There's room to improve the speed of this. I focused on a stable test/build pipeline since the desire was automated deploys to dot org.

The updated package-lock.json file is due to a merge conflict when bringing this up to date with the develop branch.

[mindctrl]

Thanks for the review. I agree that we can improve and simplify this by using better container images, cache, etc.