[1/x] Clean up automation pipeline

[andrewchang-bird]

Stack:
📚 #259 [4/x] Bump versions to 0.19.0
📚 #258 [3/x] Codemod Xcode-generated file header comments
📚 #257 [2/x] Migrate to DocC for API reference docs
📚 #256 ← [1/x] Clean up automation pipeline

Overview

Our current automation pipeline is heavily dependent on a single Makefile, which has grown quite unsightly over the past few years. This fully removes the Makefile and refactors it into a separate automation Swift executable. The new automation pipeline covers the same functionality as before, including:

• Building signed framework and generator artifacts
• Bundling the generator executable into a ZIP archive with the appropriate licensing and dylib dependencies
• Running the end-to-end and unit test cases
• Loading, unloading, and saving Xcode schemes to support Carthage

In addition, the GitHub workflows are now simplified into just two: CI and Release. This makes it easier to reason about the job triggers and reduces duplicate YAML boilerplate.

Test Plan

• CI workflows pass
• Running the automation binary locally:

% Sources/MockingbirdAutomationCli/buildAndRun.sh --help
[32/32] Build complete!
OVERVIEW: Task runner for Mockingbird.

USAGE: automation <subcommand>

OPTIONS:
  -h, --help              Show help information.

SUBCOMMANDS:
  build                   Build a project artifact.
  test                    Run a test suite.
  configure               Configure the project environment.

  See 'automation help <subcommand>' for detailed help.
% Sources/MockingbirdAutomationCli/buildAndRun.sh build --help 
[0/0] Build complete!
OVERVIEW: Build a project artifact.

USAGE: automation build [--archive <archive>] <subcommand>

OPTIONS:
  --archive <archive>     File path to store archived built products.
  -h, --help              Show help information.

SUBCOMMANDS:
  cli                     Build the command line interface.
  framework               Build a fat XCFramework bundle.

  See 'automation help build <subcommand>' for detailed help.
% Sources/MockingbirdAutomationCli/buildAndRun.sh test --help 
[0/0] Build complete!
OVERVIEW: Run a test suite.

USAGE: automation test <subcommand>

OPTIONS:
  -h, --help              Show help information.

SUBCOMMANDS:
  e2e                     Run all end-to-end tests.
  example                 Run an end-to-end example project test.

  See 'automation help test <subcommand>' for detailed help.
% Sources/MockingbirdAutomationCli/buildAndRun.sh configure --help
[0/0] Build complete!
OVERVIEW: Configure the project environment.

USAGE: automation configure <subcommand>

OPTIONS:
  -h, --help              Show help information.

SUBCOMMANDS:
  load                    Apply shared schemes to the Xcode project.
  unload                  Remove shared schemes.
  save                    Save shared Xcode schemes.

  See 'automation help configure <subcommand>' for detailed help.