Support command line arguments to display budget information

[bvanelli]

Description

The main strength of the Python library is to actually write easy to use CLI tools that could interact with the server itself.

My first idea was to implement "display only" functions as a proof of concept, and it the implementation makes sense eventually add the option to also add data. Keeping it simple, here is the proposal:

Main options:

• -o or --output: table, for table view of the entries using rich tables, or json
• --context, for selecting the context of the cli

Configuration:

• ~/.actual/ folder on home directory would hold the config.yaml file for the configuration. Basic format:

config:
   defaultBudget: <budgetName>
   output: table
budgets:
    budget_name:
        url: <url of the actual server>
        password: <base 64 version of password>
        encryptionPassword: <base 64 version of password>
        fileId: file id on the remote

Main commands:

• init: initializes an actual budget config, taking optionally --url, --password, --encryption-password, --context, --file
• version: shows library version and server version
• accounts: show all accounts
• transactions: show all transactions
• payees: show all payees
• export: generates an export from the budget (for CLI backups)