Orbofi

In the contract `OBIToken` the role `BURNER_ROLE` has authority over the functions shown in the diagram below. Any compromise to the `BURNER_ROLE` account may allow the hacker to take advantage of this authority and burn all the tokens of any holder without community awareness.  In the contract `OBI` the role `MINTER_ROLE` has authority over the functions shown in the diagram below. Any compromise to the `MINTER_ROLE` account may allow the hacker to take advantage of this authority and mint an uncontrolled amount of tokens to his EOAs without community awareness.  In the contract `OBIToken` the role `DEFAULT_ADMIN_ROLE` has authority over the functions shown in the diagram below. Any compromise to the `DEFAULT_ADMIN_ROLE` account may allow the hacker to take advantage of this authority and perform, including but not limited to, the following: - revoke the `BURNER_ROLE` from the intended account. - revoke the `MINTER_ROLE` from the intended account. - grant himself (or an account controlled by him) the `BURNER_ROLE` and perform the action described in the `BURNER_ROLE` section. - grant himself (or an account controlled by him) the `MINTER_ROLE` and perform the action described in the `MINTER_ROLE` section. 

All `OBIToken` tokens are sent to the `_vault` EOA when deploying the contract. This is a potential centralization risk as the deployer can distribute `OBIToken` tokens without the consensus of the community.

There should always be events emitted in the sensitive functions that are controlled by centralization roles.