Add bootstrap rm and bootstrap add

[Mairkur]

Hi I'm developing an app with electron using js-go-daemon and by extension js-http-client. The app doesn't need to be connected to all the default "textile ipfs node".

Moreover I have the impression, that the number of request received by being connected to the default network is too high, leading to a very reduced bandwidth.

That why I think that to be able to delete all the bootstrap addresses and to add new (private) addresses. could be great.