oranda build --release/--evergreen/--all for targeted builds

some pages, such as the artifacts and docs pages, on a tool site are archival, which is to say, you build them for each release and retain them as assets. other pages such as the install page and the home page, change with a release and independently of the release, but are not retain archivally, and are instead "evergreen".

we need to make this distinction in the tool and we need to offer a command modifier for build that can be used