Implement http API list endpoints for factsheets and scenario datatables

[jh-RLI]

Summary of the discussion

For the form to create/edit the scenario bundle, we need a list of all available tables and also factsheets (both model and framework). This list is currently generated statically. This pull requests use django's rest framework to implement dynamic http-based api endpoints that list all resources in json format.

Type of change (CHANGELOG.md)

Added

• Add http api list endpoint for factsheets (both framework & model) and datasets in the scenario topic (#1553)

Workflow checklist

Automation

Closes #1500 part of #1540

PR-Assignee

• [x] 🐙 Follow the workflow in CONTRIBUTING.md
• [x] 📝 Update the CHANGELOG.md
• [x] 📙 Update the documentation on mkdocs

Reviewer

• [x] 🐙 Follow the Reviewer Guidelines
• [ ] 🐙 Provided feedback and show sufficient appreciation for the work done