Use Ash CLI for API calls and transactions

[Nuttymoon]

Linked issues

• Fixes How to adapt to the keystore API deprecation? #46
• Fixes Use Ash CLI to perform API calls and issue transactions #68

Dependencies

• Fetch pending validators ash-rs#55

Changes

• Allow adding custom networks to Ash CLI configuration
• Use Ash CLI for all API calls and transactions
• Remove all usage of the keystore API

Breaking changes

• Remove the blockchain role. All the blockchain creation logic is now in the subnet role
• Remove/add variables of/to node, subnet, ash_cli role
• Remove the tx module that was relying on the keystore API