Adds `pulumi update` so you can deploy to the Pulumi Console (via PPC on the backend).
As per an earlier discussion (now lost because I rebased/squashed the commits), we want to be more deliberate about how to bifurcate "local" and "cloud" versions of every Pulumi command.
We can block this PR until we do the refactoring to have `pulumi` commands go through a generic "PulumiCloud" interface. But it would be nice to commit this so I can do more refining of the `pulumi` -> Console -> PPC workflow.
Another known area that will need to be revisited is how we render the PPC events on the CLI. Update events from the PPC are generated in a different format than the `engine.Event`, and we'll probably want to change the PPC to emit messages in the same format. (e.g. how we handle coloring, etc.)
This is the first change of many to merge the MuPack/MuIL formats
into the heart of the "compiler".
In fact, the entire meaning of the compiler has changed, from
something that took metadata and produced CloudFormation, into
something that takes MuPack/MuIL as input, and produces a MuGL
graph as output. Although this process is distinctly different,
there are several aspects we can reuse, like workspace management,
dependency resolution, and some amount of name binding and symbol
resolution, just as a few examples.
An overview of the compilation process is available as a comment
inside of the compiler.Compile function, although it is currently
unimplemented.
The relationship between Workspace and Compiler has been semi-
inverted, such that all Compiler instances require a Workspace
object. This is more natural anyway and moves some of the detection
logic "outside" of the Compiler. Similarly, Options has moved to
a top-level package, so that Workspace and Compiler may share
access to it without causing package import cycles.
Finally, all that templating crap is gone. This alone is cause
for mass celebration!
This change just moves the assertion/failure functions from the pkg/util
package to pkg/util/contract, so things read a bit nicer (i.e.,
`contract.Assert(x)` versus `util.Assert(x)`).