Add manifest support to depend-info

[GordonSmith]

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Is your feature request related to a problem? Please describe.
vcpkg.exe depend-info requires a package name and ignores local manifest

Proposed solution
Should behave in a similar way to vcpkg.exe install and build a graph of all the dependencies in the vcpkg.json manifest

Describe alternatives you've considered
Manually running vcpkg.exe depend-info for each item in my manfiest file and merging the responses

[moritz-h]

For me it worked by adding the project root directory with the vcpkg.json to the list of overlay port directories. Then I could just ask for the depend-info of the whole project at once.

cd project_root_dir
path/to/vcpkg depend-info --overlay-ports=project_overlay_ports --overlay-ports=. my_project

I'm running this command from the project root directory, because that way also the vcpkg-configuration.json with additional registries is also recognised automatically.

[AlexanderLanin]

This works perfectly, but it's not really intuitive ;-)