fix: support keychain without pass (#3212)

- add support for ed25519 and secp256k1 keys for the ipfs PeerId
- add support for using ed25519 and secp256k1 keys with ipns
- add support for keychain without a pass, this fixes several keychain commands
- fix `name publish`, ttl should be optional but wasn't being allowed

Includes changes in ipfs/js-ipfs#3208

Key gen and key listing now works:
```sh
$ jsipfs key gen --type=ed25519 my-ed-key
generated QmUPJZ3ghsnkRVgYjrMrSC8MbbZTzcezn6mH7vY9vTbrMY my-ed-key

$ jsipfs key list
QmUPJZ3ghsnkRVgYjrMrSC8MbbZTzcezn6mH7vY9vTbrMY my-ed-key
QmYPxJJb8Mpa6JjQj7hCTF4ajn2SE1HFLRoAnCbymTGzyC self
```

IPNS Publishing now works properly, including using other key types:
```sh
jsipfs name publish -k my-ed-key /ipfs/QmP7WDyEdkFu2nfj35SUEB7fk3iKCHpcrCVbGk1HXZU22a
Published to 12D3KooWGmSq6u3yZeXqeqSmQpJWKQGGdCxrZQAUZBzsbSM2kCE6: /ipfs/QmP7WDyEdkFu2nfj35SUEB7fk3iKCHpcrCVbGk1HXZU22a
```

I also fixed a couple of the example tests, they weren't waiting for IPFS to start before executing the tests, which could cause them to intermittently fail.

BREAKING CHANGE: remove support for key.export over the http api

Author: jacobheun

src/key/export.js

@@ -5,6 +5,5 @@ module.exports = config => ({
   list: require('./list')(config),
   rename: require('./rename')(config),
   rm: require('./rm')(config),
-  export: require('./export')(config),
   import: require('./import')(config)
 })