feature: [adapter] Added more typing rules and tests

[jonathanlukas]

Description

Currently, only typing one variable in one process is possible. This PR enables:

• one variable globally
• one variable in some processes
• one variable in one process

Additional context

closes #387

Testing your changes

There are new, separate tests that assert the behaviour of the different typing rules

Types of changes

• Bug fix (non-breaking change which fixes an existing open issue)
• New feature (non-breaking change which adds functionality to an extension)
• Breaking change (fix or feature that would cause existing functionality of an extension to change)
• Documentation update (changes made to an existing piece of documentation)

Checklist:

• My code adheres to the syntax used by this extension.
• My pull request requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the Camunda Community Hub documentation.
• I have read the Pull Request Process documentation.
• I have added or suggested tests to cover my changes suggested in this pull request.
• All new and existing CI/CD tests passed.
• I will /assign myself this issue, and add the relevant [issue labels] to it if they are not automatically generated by Probot.
• I will tag @camunda-community-hub/devrel in a new comment on this issue if 30 days have passed since my pull request was opened and I have not received a response from the extension's maintainer.

[github-actions]

Test Results

  25 files  +1    25 suites  +1   1m 55s ⏱️ ±0s
215 tests +3  215 ✔️ +3  0 💤 ±0  0 ❌ ±0 
331 runs  +3  331 ✔️ +3  0 💤 ±0  0 ❌ ±0 

Results for commit cb9a0b8. ± Comparison against base commit b70b746.