Allow users to assign manual accounts to an "Institution" and edit account details after creation

[zachgoll]

Feature Overview

Currently, account management is limited to "manual" accounts that cannot be edited after creation and cannot be assigned to any institution.

Requirements

If there is a missing / incorrect requirement, please leave a comment before starting work on this.

• Can manage a list of institutions in settings (similar to Tags, Categories, Merchants)
• Can edit account details after creation (name, institution)
• Can assign an Institution to an account, which will then become the "grouping" in the accounts management view