Cache generated addresses

**Feature description**
Cache addresses generated by `generateAddresses` endpoint

**Is your feature request related to a problem? Please describe.**
Address generation is a very slow process

Example:
```
1 address = 351ms
2 addresses = 680ms
3 addresses = 1s
4 addresses = 1.336s
8 addresses = 2.652s
```

**Describe the solution you'd like**
some sort of key value store with a unique identifier derived from the `seed` as key and list of addresses as value

persist to disk maybe ( possible security risks )

**Describe alternatives you've considered**
limit addresses to 1 so no performance issues