Add list accounts API

[mederic-p]

Closes #84

Overview

This PR adds the list accounts API.

Usage

        let params: PaginatedListParams<Account> = PaginatedListParams<Account>(page: 1, perPage: 10, sortBy: .name, sortDirection: .ascending)
        Account.list(using: self.apiClient, params: params) { (result) in
            switch result {
            case let .success(data: paginatedAccounts):
                let accounts = paginatedAccounts.data
                print(accounts)
            case let .fail(error: error): print(error)
            }
        }