Runtime stacks having mentions for che

[slemeur]

https://codenvy.com/docs/getting-started/stacks/index.html

For details on this, see Building Extensions and / or start a dialog with the core Che engineers at che-dev@eclipse.org.

See also in the content, many references still pointing to Che.

[riuvshin]

who is on this? do we need this for 5.2.0 ?

[riuvshin]

@JamesDrummond @bmicklea do we plan this tobe done for 5.2.0? if no please drop milestone