Names of fields `author` and `maintainer` in the `package.yaml` file
have been changed to `authors` and `maintainers` respectively, and their
format has been modified.
Projects created in older versions may not be compatible.
1. Implements the `enso install distribution` command.
2. Implements a DistributionManager which is used for managing installation
layout in the launcher.
PR #1034Resolves#1010
1. This commit adds an extensive library for parsing commandline
arguments and formatting output.
2. It implements the expected CLI for the launcher.
3. It turns off parallel execution on the CI in hopes of making it
more stable.
4. It implements plugin support in the launcher.
