add metrics plugin

[sparkoo]

Signed-off-by: Michal Vala mvala@redhat.com

What does this PR do?

As a part of workspace monitoring effort we would need to enable metrics plugin in che-theia.

What issues does this PR fix or reference?

eclipse-che/che#13270
eclipse-che/che#14888

Release Notes

n/a

Docs PR

n/a

[che-bot]

E2E Happy path tests of Eclipse Che Single User on K8S (minikube v1.1.1) has been successful:

• build details
• logs and configs
• "che-theia" docker image: maxura/che-theia:520
• "che-theia-endpoint-runtime" docker image: maxura/che-theia-endpoint-runtime:520
• "che-remote-plugin-runner-java8" docker image: maxura/che-remote-plugin-runner-java8:520
• "che-remote-plugin-kubernetes-tooling-1.0.0" docker image: maxura/che-remote-plugin-kubernetes-tooling-1.0.0:520
• Happy path tests DevFile

[skabashnyuk]

@benoitf @evidolob wdyt. Can we enable this plugin by default?

[sparkoo]

cc: @JPinkney