OUSD - harvesting strategy rewards open to public

Currently, we are using Chainlink Keepers to collect reward tokens on a weekly basis, swap them to USDT and send them to the Vault.

With the goal of making OUSD more decentralised, this proposal suggests lifting restrictions and allowing anyone to harvest reward tokens. This will also make it possible for harvests to occur more frequently, which will lead to a smoother APY. Harvests are incentivised by dividing a share of the reward token proceeds with the caller of the harvest function. The percentage share of reward tokens awarded to the caller is configured on a per-strategy basis:

Compound strategy: 1% Aave strategy: 1% Convex strategy: 1%