Refactor luma account tests

[gregor-RW]

Cleanup of Account Spec tests for Luma theme. Things done:

1. Break down the Account Activities and create Account login/logout and Account Address Activities to better separate the test logic (and optimize the usage of before/beforeEach/after in each of them)
2. Introduction of Magento2RestApi.replacePassword() to not rely on the frontend to change the password back
3. Introduction of Account.deleteAddress() to handle Addresses cleanup after Account Address Activities tests
4. Left some TODOs that can be extracted as separate issues and can be a good FirstIssue type for the project

[gregor-RW]

None of the GitHub Actions CI tests relate to Luma. Can someone manually confirm that its working?