Rename this repo/library to ci-environment

[aslakhellesoy]

Is your feature request related to a problem? Please describe.
I am building a library that needs the CI detection logic in this library, but it doesn't need the messages dependency.

Describe the solution you'd like

• Rename this repo to cucumber/ci-environment
• Rename this library to:
  • NPM: @cucumber/ci-environment
  • Gems/Ruby: cucumber-ci-environment / Cucumber::CiEnvironment
  • Maven/Java: io.cucumber:ci-environment / io.cucumber.cienvironment
• Remove messages dependency and return a custom CiEnvironment class/struct instead

Describe alternatives you've considered
I considered using the library as-is, but given the size of messages it seems unnecessary bloat

Additional context
Cucumber implementations that currently depend on create-meta should be upgraded to depend on the new library, and create the Meta message from the CiEnvironment object returned by this library.

[aslakhellesoy]

Fixed by #34