I don't see the point. Bootstrap isn't that hard to get started with just about any PHP framework. Unless i've been doing it wrong. Add the html into the views, link to the js and css assets, donezo.

Or, if you want to get clever, add it to a Composer repo, and have a shell script run after the update that copies stuff from the vendor folder into /public (that tripped me up on pagodabox but it's doable) and now you have Bootstrap running with auto updating and dependency management.

Why does this need to be a service?