Add support for Carthage

[mluisbrown]

This adds support for installing the Prelude frameworks using Carthage.

Basically:

• remove the gitignore for .xcodeproj files
• use the Prelude.xcodeproj file generated by make xcodeproj as a starting point, removing the Diff, SnapshotTesting and WKSnapshotConfigurationShim targets from the Run and Archive builds as they are incompatible with arm64 builds and aren't required when building as a dependency.
• Add swift-tagged as a Carthage dependency (at version 0.2.0) using submodules (carthage checkout --use-submodules) and include the Tagged project into the Prelude workspace.
• Delete the SPM created Tagged dependency from the Prelude project and use the framework built from the Tagged sub-project as the dependency for Prelude.

make xcodeproj will overwrite Prelude.xcodeproj so this doesn't affect building and testing using SPM.

[mbrandonw]

@mluisbrown hey thanks for this and sorry for the radio silence! we're interested in doing this (and the same with some of our other packages), but we need a bit more time to figure out a sustainable way to do this. so far we've been having a bit of pain supporting Carthage.

Thanks again!

[mluisbrown]

Thanks for letting me know @mbrandonw. What are the issues with Carthage that you are facing? At work we are looking to include Prelude into one of our frameworks and we would really need Carthage support for this.

[sloik]

What about cocoapods? :)

[stephencelis]

Hey @mluisbrown (and @sloik)! It's been awhile but we've been exploring this more recently and have an update here:
#113 (comment)

[stephencelis]

And the world turns :) We've been slowly phasing out support for non-SPM tools, and Prelude's been in a bit of a "maintenance mode," so we're going to finally close this out. Thanks for coming along on the journey 😄