Adheres to https://zeitgeist.subsquare.io/post/2

Set the total number of collator candidates selected per round
- changes are not applied until the start of the next round

- **Problem Statement:** Lack of clarity on the Polkassembly Referendum process.
- **Significance:** Ensuring transparency and understanding for Polkassembly users.
- **Proposed Solution:** Implementing a detailed guide on the Polkassembly Referendum process.
- **Expected Outcomes:** Increased user engagement and informed decision-making.

#12 Increase active collator set size to 20