Support file based build configuration

[ghaith]

Is your feature request related to a problem? Please describe.
Support building a project using a build description file.
The description file contains:

• The sources to build (Could be globs)
• The libraries to include/link to
• Libraries are specified by a path.
• Anything in the include directory of the library is included.
• SO files should be located under their target folders in the lib directory
• The output type (Static/Shared/Executable)
• The output filename
• Packaging Information
  Packaging information contains a list of commands to be executed after the build/linking is done

Optionally, the description could also include metadata :

• Project Name
• Version
• Authors
• Website

Describe the solution you'd like
Introduce a new subcommand build.
The build subcommand will look for a plc.json file to read the configuration
It can also take the configuration as an argument

• The build would happen in a build directory in the project, or if specified with --build-location another directory
• The build would be ran for the default target, unless a --target is passed with a target triple.