Add option to exclude/include installed package metadata in metadata subscription

Issue #964 resolved
Tony White created an issue

Would be good to have an option to exclude/include the metadata for installed packages when setting up the metadata subscription.

We do our deployments through the API from GIT but do not want to include the metadata related to installed packages due it not being under our control. But we need to pull down the complete environment to compare what we changed etc but having the installed packages adds a lot of noise when using the 'All/Package' option, and deselecting the components that are from the installed package can be tricky and time consuming when setting up a new project...