Added new env variable to separate staging and production discussions

[babakamyljanovssw]

Relates to #1567

As per feedback from Matt W, current implementation stores staging and production discussions in same place which leads to staging rules URL added to the discussion body.

I think the best way to avoid this issue or any staging and production crossing issues is we can store staging discussions in separate repo.

• I created new empty repo - https://github.com/SSWConsulting/SSW.Rules.Staging.Discussions
• Updated GISCUS_REPO_NAME, GISCUS_REPO_ID, GISCUS_CATEGORY_ID secrets for each environment

New behavior:

• Production discussions will be created on SSW.Rules.Content repo | Rules Discussions category - https://github.com/SSWConsulting/SSW.Rules.Content/discussions/categories/rules-discussions
• Staging discussions will be stored on SSW.Rules.Staging.Discussions repo | Rules Discussions category - https://github.com/SSWConsulting/SSW.Rules.Staging.Discussions/discussions/categories/rules-discussions

Figure: Staging URL was added to discussion that this discussion points to production rule as well