Send coverage to codecov again

[kesselb]

• Added the codecov token to drone secrets. That makes it easier to replace it.
• The switch pull_request / no pull_request looked superfluous to me. https://github.com/codecov/codecov-bash/blob/ac57e523b06dd4381e6e872677e74b4f95c0939a/codecov#L666-L677 (only the commit seems to be missing).
• Docker images used are not rebuild automatically hence php7.x:latest should work for most pipelines.
• nodb-codecov and db-codecov use -Z now: Exit with 1 if not successful. Default will Exit with 0. If for some reason xdebug is missing (or something else) those pipelines should fail.

[georgehrke]

@kesselb What's the status here? :)

[kesselb]

For some builds the coverage is reported again to codecov 👻

Some lines (that are related to codecov on jobs with missing xdebug extension) are commented. I would like to keep them for now. Probably someone else want's to update the docker images (or even better switch to pcov) for the jobs without coverage.

Feel free to move this to 20 (or remove the milestone). It's not really related to a release.

[MorrisJobke]

makes sense 👍