Inline package upgrades test

[akrmn]

Updates the upgrades tests to allow for "test dars" to be generated inline for test files using a comment yaml syntax, and cpp pragmas to modify per version. This allows our upgrades tests to be self contained and still simply daml files. The syntax is as follows

{- PACKAGE
name: <the-package-name>
versions: <number of versions to create as an int, will generate 1.0.0, 2.0.0, ..., n.0.0>
-}
{- MODULE
package: <a-package-name>
contents: |
  module <Name.Of.The.Module> where
    <write daml code here>
    template Example with p: Party where signatory p
-}

Module names can be arbitrarily long, the correct project structure will be generated. All daml code after the contents: | should be indented once more than the contents above it. Packages (or more specifically, dars) will be generated with the naming scheme <package-name>-<package-version>. e.g. my-package-2.0.0.

The contents supports the special comments -- @V <space separated versions> to filter code based on version. i.e. if you wanted a field only in v2, you'd write within contents

template Upgraded with
    p: Party
    anotherField: Optional Int -- @V 2
  where
    signatory p

The lines with @V comments are kept when building the dar with a version present in the comment (i.e. -- @V 2 3 will be kept when building versions 2.0.0 and 3.0.0), otherwise they are dropped. The lines without such comments are always preserved.

[samuel-williams-da]

~~Maybe also a little readme describing the format?~~ I have now done this

[remyhaemmerle-da]

Module names can be arbitrarily long, the correct project structure will be generated.

Not sure what you mean here, but LF restricts module names to 1000 chars including dot.