Combine image and archive modes

[blb@…]

Combining the image and archive modes into a new image-through-archives and always enabling it buys several advantages:

• no more need to worry about links for image mode as all inactive ports would simply exist in the archive instead of being fully installed in ${prefix}/var/macports/software
• configuration settings for these (portinstalltype, portarchivemode, portarchivepath, and portarchivetype) can be removed simplifying code and macports.conf
• always building/using archives should bring MacPorts closer to supporting install-from-binaries instead of just from source
• removal of archive-specific targets/actions (since they'd be merged into the activate area) simplifies MacPorts base code

I'll create a branch for development​ to keep this off of trunk until it is ready for more widespread testing.

[afb@…]

It would also allow for saving disk space, by allowing compression of inactive ports.

[afb@…]

And fix #13143, too.

[nox@…]

I think this is a good idea, but telling it will permit to save some disk space seems wrong to me, currently a port consumes almost the same disk space active or inactive, with images-through-archives, an active port will consume twice as much as an inactive port. As most users have only active ports, I think this argument is incorrect.

[nerdling (Jeremy Lavergne)]

Cc Me!

[jmroot (Joshua Root)]

r77511