Fast passphrase hashing

[lucksus]

PR summary

Use the test config for the password hash to make it much faster.

The default config for the passphrase hashing is set to super-secure: the hashing algorithm is designed to take a serious amount of resources to prevent attacks against the keys if an attacker got hold of the encrypted keys but not the passphrase.

The problem with this is: starting Holoscape takes a long time. On slow machines it will trigger the 60 seconds timeout which then shows an error and opens the logs.

Note:
This is a breaking-change since it will break keys/passphrases: you can't decrypt a key that was created with the old config when starting a new conductor - the new hash config will result in a different hash.

This means users have to re-create keys with the new version this change gets in.

testing/benchmarking notes

Tried in Holoscape: makes booting and installing hApps much faster since decrypting keys is the most time consuming task in both workflows.

followups

Ultimately we should find the right balance of security and usability. But for now, as long as we are in alpha at least, we can configure the passphrase hashing to be very simple.

changelog

• if this is a code change that effects some consumer (e.g. zome developers) of holochain core, then it has been added to our between-release changelog with the format

- summary of change [PR#1234](https://github.com/holochain/holochain-rust/pull/1234)

documentation

• this code has been documented according to our docs checklist

[thedavidmeister]

approved given that we are still testing things

[neonphog]

I'm cool with this so long as we have some presence in the tree for fixing it in the future. Couple thoughts:

• Even in secure mode, this shouldn't be taking so long - is it still doing a hash for every agent_id? We need the keystore to just do the password hash once per conductor and then use that shared key to do crypto on the subkeys
• At some point, we may actually want a separate system service that can act as the keystore "vault" for a system, that will actually only do the password hashing once for a whole system, and multiple conductors.