some code reviews for Bootstrap and other contracts

[adu-web3]

Description

I get some thoughts when reviewing the Bootstrap contract and other contracts, so I just share here for discussion with @MaxMustermann2 and other team members

https://github.com/ExocoreNetwork/exocore-contracts/blob/712cfd5d930a55379a77f59ba32a6d0ed8292b05/src/core/Bootstrap.sol#L212-L217

I think we should check that name is not empty string here

https://github.com/ExocoreNetwork/exocore-contracts/blob/712cfd5d930a55379a77f59ba32a6d0ed8292b05/src/core/Bootstrap.sol#L281-L291

iteration over registeredValidators is expensive, so maybe we should add a new state variable mapping(string => bool) public nameUsed to determine whether a name has been used. this is also mentioned in #18

@MaxMustermann2 what do you think?

[MaxMustermann2]

Sure I will do it today. In addition to the name, a similar check for consensus key will be added.

[MaxMustermann2]

Included in #74