#1314 Remove dependencies on legacy cca-extensions. (state: open)

Description

I removed the dependency on the package contao-community-alliance/dependency-container because it requires pimple/pimple in version 1.0. This conflicts with Deployer, which requires Pimple in version 3.

Checklist

• Read and understood the CONTRIBUTING guidelines
• Created tests, if possible
• All tests passing
• Extended the README / documentation, if necessary
• Added myself to the @authors in touched PHP files
• Checked the changes with phpcq and introduced no new issues

I'm not sure if this will break third party extensions but I also strongly doubt that anyone is still using these features... So I am undecided on this one.

@richardhj can you push this at gitlab? base ist feature/2.2.0