Do port/parameter substitution in environment variables

[sverhagen]

I had a need for port/parameter substitution in environment variables. I wanted to set the database URL on my second container, that had the port as determined for the first container.

E.g., the second container had something like this:

<env>
    <DATABASE_URL>jdbc\:mysql\://${env.DOCKER_HOST_HOST}:${database.port}/</DATABASE_URL>
</env>

The code in the merge request does this, plus a few minor other snippets.

[sverhagen]

Added the sign off as required here. Is there anything else I could do to move this forward? Thank you.

[rhuss]

I will have a look at it ASAP (probably at the end of this week). I think its a quite nice feature, so you can be pretty sure that the PR will be applied after a review.

[rhuss]

Sorry for the delay. Applied the PR to integration, will be available in 0.11.4 soon.