CDI context propagation

In CDI spec, the context propagation was not addressed in the spec. The original ticket was raised:

> Key: CDI-587
> URL: https://issues.jboss.org/browse/CDI-587
> Project: CDI Specification Issues
> Issue Type: Epic
> Components: Contexts
> Affects Versions: 1.2.Final
> Reporter: Romain Manni-Bucau
>
> The overall idea is to ensure that it is not cause the code becomes asynchronous/reactive/... that we loose the instances or get another context.
> An example is starting an AsyncContext in a servlet.
> One proposal is to add a flag to ask for propagation of the context in async managed threads: @RequestScoped(inherited = true) which would reuse the same instances for these "new" threads.
> Note however this issue is not only bound to servlets even if it is the easiest example.
> The original thread disucssion on the list: http://cdi-development-mailing-list.1064426.n5.nabble.com/RequestScope-Life-Cycle-td5712701.html

In MicroProfile Context Propagation, some effort was made to address the context propagation and the implementation was made in Weld. However, it has a some issues, such as https://github.com/eclipse/microprofile-context-propagation/issues/167

Start by reading the CDI-587 context-propagation proposal and the linked mailing-list discussion. Then compare the MicroProfile Context Propagation work, the Weld implementation, and issue 167. Done would require a concrete, agreed approach for addressing context propagation in the CDI specification.

Written by the indexing model from the issue text.