Consider improving CLI API

[jondequinor]

Current:
--tmp has no default, is passed onto komodo.build as builddir but is largely ignored by the builders
--cache has no default, becomes outdir in komodo.fetch (which defaults to . and is created). It is also cd-ed into to ease tar and pip calls I assume. Also passed onto komodo.build as dlprefix, which is used to find e.g. find downloaded packages.
--workspace has no default, but will just become the directory from where you invoked kmd. The activators are assumed to be here if the folder exists. If the folder does not exists, the activators are copied over.
--fakeroot has no default, but becomes fakeroot = os.path.abspath(args.release) which probably has its reasons. However, in komodo.build it is either set to prefix via the cli, or to .. This is outright confusing. It's also a bool option.

cache is also not a cache the way I understand it, as things are built/moved around in there after fetching it. I think tmp is better suited to do temporary things pertaining to the build, whereas the cache could serve multiple builds.

In conjunction with #124, this setup makes komodo unnecessarily hard to understand. This is aggrevated by a bunch of cd operations.

In conjunction with #122, preparatory steps for a komod build involves copying stuff from here to there.

Can you even build komodo without cloning komodo (and of course komodo-releases)?

Maybe komodo could take a repository file, a release file, and a working directory (in addition to a prefix)? All other things should live inside komodo and the komodo pip package.