fix acr url and improve appname and image tag defaults

[davidgamero]

Description

• Update the acr generated link to use the azure.cr.io url
• default image tag to latest when no tag is provided on the context
• change port prompt to 80 to match the default value
• strip invalid characters and lowercase basename to produce valid default app name

Fixes # (issue) Feature # (details)

Type of change

Please delete options that are not relevant.

• [X] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration. Is it a breaking change which will impact consuming tool(s).

• [x] Existing tests pass

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] 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
• [x] Any dependent changes have been merged and published in downstream modules