Print "@version" when talking about port versions more frequently.

[BillyONeal]

In microsoft/vcpkg#35164 there was some confusion where a customer thought vcpkg ci was building an old version of openvino because we only printed the version to build for the --dry-run prepass and didn't print the version to build for the actual build. The customer thought we were building the old version rather than the new version as a result.

This change ensures we print the version we are discussing after "Installing" or "Building" and consistently uses the "packagespec@version" form in all the places. For consistency the "packagespec -> version" form we used in a few places is replaced with the @ form.

[dg0yt]

The customer thought we were building the old version rather than the new version as a result.

The customer vcpkg team members ...

[dg0yt]

With regard to CI, it is probably still more important to omit unnecessary output for --dry-run (like initially submitted).
Maybe even move the dry-run to a separate step?

[BillyONeal]

With regard to CI, it is probably still more important to omit unnecessary output for --dry-run (like initially submitted).

Since that change was going to require touching docs and stuff here I was lazy and just made us consistently print the version. I don't have strong opinions on next steps; perhaps --parent-hashes should imply 'parent hashes is all I am doing' and make switches like --dry-run have no effect. And possibly --dry-run just shouldn't exist for ci in the first place... I suspect that the only reason it is there is copy pasta from install once upon a time.

In the future I would like to make the ci command smarter by examining what the user actually modifies now that I understand git well enough to write this, but it's not going to be a priority anytime soon.