New Polkadot Hydration farms & adjustments

This proposal is the SECOND of THREE referenda outlined in referendum #28 (https://hydration.subsquare.io/referenda/28).

Specifically, this proposal will:

Adjust APR on:

• CFG - reduce yield per period by 25%
• INTR - no further rewards, farm to close once current rewards run dry
• KILT - reduce yield per period by 50%
• vASTR - reduce yield per period by 50%

Create new global farms:

• tBTC
• AAVE

Note - creation of the global farms does NOT activate them - the third and final referendum (which will follow some hours after this one) is required to activate the new tBTC & AAVE farms