radically simplify settings needed in ods-configuration/ods-core.env.sample

Is your feature request related to a problem? Please describe.
ods-core.env.sample contains a lot of 'unneeded' information

1. host names of OCP routes
2. duplication of information (e.g. no $ substitution)
3. other data that we can easily get out of ocp

This can lead to a wealth of (configuration) errors - that we don't want to have ... and saw in the work for @georgfedermann - edp in a box

Describe the solution you'd like
the solution is fourfold

1. The config file should be SUPER simple: perfect world - some attributes need to be filled only:
   1.1 bitbucket url
   1.2 jira url
   1.3 confluence url
   1.4 ocp api host

2. All routes' hostnames should be OCP created - and not configured in the env file (https://github.com/opendevstack/ods-core/blob/master/configuration-sample/ods-core.env.sample#L44)

3. Host/Url route combos that that come from OCP should be updated automatically in the ods-core.env within the respective make targets, after the installation of a component. I would expect some sort of amend of ods-core.env on the fly.

4. $ substitutions should work (https://github.com/opendevstack/ods-core/blob/master/configuration-sample/ods-core.env.sample#L43-L47)

Additional context
follow up to #517 / @metmajer @michaelsauter - fyi

Start with configuration-sample/ods-core.env.sample, especially the route and substitution examples around lines 43–47, then trace the respective make targets that update ods-core.env after component installation. Review follow-up issue #517 for context. Done means the sample needs only the listed external URLs and OCP API host, while route hostnames are obtained from OCP and substitutions work.