Oracles: Add Colend to Switchboard supported protocols

[mgild]

Add Colend to Switchboard supported protocols

Colend uses Switchboard oracles in conjunction with Pyth for robustness of pricing sources

Oracle documentation referencing how different price sources are used can be found here:
https://colend.gitbook.io/home/resources/security-and-risks/oracles#motivations-for-using-a-pull-oracle-over-a-push-oracle

[realdealshaman]

Hey @mgild, thanks for the PR! The docs currently note Pyth as the primary oracle with Switchboard as a complementary provider. Could you add any supporting info or rationale that shows Switchboard is also intended to be a primary source? Or that show that a median-based approach is being used? Otherwise, we’d need to add the oraclesBreakdown key and include Switchboard there as type: "Secondary"