feat: add support for multi accounts

[t1agob]

Description

This PR adds support for multi-account configuration to scaffolder actions. It introduces no changes for the end user and adapts to the configuration set in app-config.yaml. If multiple accounts are configured the user will see the list of all Escalation Policies in all accounts with the reference to it's source account.

At creation time, the scaffolder will select the correct account to deploy the service to depending on the select escalation policy/account pair selected.

Issue number: N/A

Type of change

• New feature (non-breaking change which adds functionality)
• Fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• Changes generate no new warnings
• PR title follows conventional commit semantics

If this is a breaking change 👇

• I have documented the migration process
• I have implemented necessary warnings (if it can live side by side)

Acknowledgement

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