Kubernetes extension should not produce env vars with slashes when mapping mp-rest client config to env vars

Given an application.properties like the following:

foo/mp-rest/url=http://localhost:8080

quarkus.kubernetes.env.mapping.foo/mp-rest/url.from-secret=something-parameters
quarkus.kubernetes.env.mapping.foo/mp-rest/url.with-key=foo.url

The generated kubernetes.yml uses the FOO/MP_REST/URL env var, which is invalid, as noted by https://github.com/eclipse/microprofile-rest-client/issues/171 and https://github.com/eclipse/microprofile-config/issues/420 in the past.

We should replace / with _ and figure out if MP-Config actually can do the reverse mapping.

[radcortez]

I think we should provide a dotted version of /mp-rest/url to improve the user experience and to not confuse people. I mean you can still use it but a dotted version will also be accepted and map to the right configuration.

[gsmet]

Well, if we didn’t want to confuse people, we would have proper Quarkus config 😃