Migrate build system to the main apalache repo?

[shonfeder]

We have discussed moving the build system (but not the specs) to the main apalache repo.

Benefits:

• Possibility of integrating CI easier
• All code in one place
• Would make it slightly easier to build from source
• Essentially moves us towards a monorepo development practice

Draw backs:

• Introduces tech debt (if we don't do a re-write first)
• Could encourage tighter coupling between systems that don't really need to be tightly coupled
• Takes some labor

Requirements

• Would need to rework the build system to pull in the the specs from a remote repo.

[shonfeder]

Suggested here: #15 (review)