Add tests for utils/convenience functions

[lasconic]

There are several utils functions in the project such as

get_cryptocurrency_by_code
get_bank_account_type_per_name
guess_security
add_user_security_by_symbol
add_user_security_by_symbol_to_account
add_user_security_to_account
add_imported_securities_to_account
get_holdings_account_per_name_or_id
add_checking_saving_account
add_user_crypto_by_code
get_user_crypto_by_code
update_user_crypto_by_code
delete_user_crypto_by_code

They need to be tested. The GET ones can be tested on the share demo account. The POST/add ones... to be defined.

[lasconic]

The GETs are in with #85