Make it possible to run "npm start" from a chosen project

[mrosvik]

The different projects are sharing atoms, molecules and organisms, but have their own templates and pages. To make the build go faster, it should be possible to start the build in gulp from a specific project, so it builds all atoms, molecules and organisms, but only the templates and pages from portal / infoportal / altinnett / brreg.

[matsgm]

A workaround is temporary moving the "maler" and "sider" for the project you don't want when building the patterns. The build time is reduced from almost 5 minutes to 1.5 min.