add empty seleton for industry ccu

[JakobBD]

Purpose of this PR

I don't even want to merge it into develop yet, but would like to discuss the implementation with you.
@whitenightZhang is going to use it for the chemicals branch, and we will merge both together.
Obviously, teCUPrc is supposed to get some entries for process based chemicals.

Type of change

(Make sure to delete from the Type-of-change list the items not relevant to your PR)

• Bug fix
• Refactoring
• New feature
• Minor change (default scenarios show only small differences)
• Fundamental change
• This change requires a documentation update

Checklist:

• My code follows the coding etiquette
• I performed a self-review of my own code
• I explained my changes within the PR, particularly in hard-to-understand areas
• I checked that the in-code documentation is up-to-date
• I adjusted the reporting in remind2 where it was needed
• I adjusted forbiddenColumnNames in readCheckScenarioConfig.R in case the PR leads to deprecated switches
• All automated model tests pass (FAIL 0 in the output of make test)
• The changelog CHANGELOG.md has been updated correctly

Further information (optional):

• Test runs are here:
• Comparison of results (what changes by this PR?):

[fschreyer]

Hi, I'd suggest that we meet once such that I understand the context of what you are currently developing. As it seems that you are moving part of what was previously in the energy supply system of REMIND to the chemicals sector, we would need to make sure there are no doublings / inconsistencies with what will remain in the energy system / core of REMIND.