Add native ether support in Vault and remove all references to EtherToken

[izqui]

Original conversation: aragon/aragonOS#245

[sohkai]

Dean's https://github.com/decanus/dynamic-vault is a complete upgrade over our existing system; I love it. It's exactly what I was looking for in terms of extensibility / feature detection in the "payment router" but much more elegant.

Totally @izqui's idea, but in writing: we could set this up similar to the run scripts app and have the vault delegate into the "connector" contracts for functionality.

[izqui]

I will be working on this today and try to squeeze it into the release :)

[bingen]

Ya, that dynamic vault is really nice!!

[gasolin]

Wow! dynamic vault looks cool and definitely like to have it 👍
Though just in case I saw the rest of works for 0.5 milestone are around test and increasing the test coverage. Introducing a new contract feature (which may need extra audit) at last time (I saw in aragon.chat the release might happen in this week?) increase the risk to deliver the short-term goal. And I think dynamic vault deserves a well-thought UI companion to handle new token types like NFT #44.

[izqui]

The release is testnet only, and this changes are going to make it into the release without problem. Auditors are going to be reviewing this leading to mainnet launch.

Actually interesting thought about NFTs, it is maybe not a crazy thought that we can do a NFT connector rather than another Vault. We won't be working on this right away but interesting.