Dev Ops: Customize README.md on first-install

[mariacha]

Right now the README.md is just the badges for how the site is performing: https://github.com/United-Philanthropy-Forum/kmc-tester/blob/master/README.md

We should also provide a link to instructions on how to use the site locally. That link is currently here: https://github.com/United-Philanthropy-Forum/km-collaborative/wiki/Local-development . (It could also be a README somewhere.)

Dev

• [ ] Add a script that grabs a link to https://github.com/United-Philanthropy-Forum/km-collaborative/wiki/Local-development and puts it at the top of the README under the badges with the header "## How to develop locally". This could be added to the scripts/composer/ScriptUpdater.php as another method "updateREADME", which can then be added to the post-create-project-cmd command in the composer.json file.
• [ ] Update this project's README to note that change under the "Maintaining this project" section: https://github.com/United-Philanthropy-Forum/km-starter-kit#maintaining-this-project
• [ ] Add a link to this wiki page about how to update the site: https://github.com/United-Philanthropy-Forum/km-collaborative/wiki/Applying-a-release-to-a-site