198 refactor the authlayout snackbar to use the alerts system

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

This PR provides:

AuthLayout snackbar integration with the Alerts system

Closes #198

Type of change

Please delete options that are not relevant.

[ ] Bug fix (non-breaking change which fixes an issue)
[x] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
[ ] This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce the cases. Please also list any relevant details for your test configuration

[x] Unit tests
[x] E2e tests
[x] Manual test

Instructions:

1. Run the development server and client
2. Log in using credentials, username: dev@camba.coop, password: 123

Expected result: an error snackbar should appear with text: The username or password is invalid

Checklist:

The following options in bold are required for a PR approval. Please check the boxes only if necessary, it help us minimizing the reviewing process.

[x] I have performed a self-review of my own code
[ ] I have commented my code, particularly in hard-to-understand areas
[ ] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes

Cambalab / vue-admin