Extract kyma-on-btp terraform resources into its own reusable module

[Cortey]

Description
Extract "kyma-on-btp" terraform resources into its own reusable module so that it could be sourced from github whenever its needed in CI pipelines (here or here)

AC

• module should be hosted on new dedicated github.com publicly
• module should define its input parameters (see hint below)
• module should include all necessary providers
• module should be used in sample kyma-automation-demo pipeline
• module should be used in integration tests of docker registry kyma module

Reason
Terraform resources for kyma-on-btp should be extracted into its own reusable discrete unit so that it could be reused and sourced from a single source on github.
This way it would become a maintainable tool that helps customers managing lifecycle of kyma resources during continuous integration of their applications.
kyma-project/kyma#18198

Attachments
https://github.tools.sap/otters/kyma-automation-demo/tree/main/tf
https://developer.hashicorp.com/terraform/language/modules
https://dev.to/lechnerc77/-mind-the-terraform-modules-3p11

Hint
Parameters should allo passing:

• global account id(required)
• subaccount id (mutually exclusive with new subaccount name; one of them must be defined)
• new subaccount name (mutually exclusive with subaccount id; one of them must be defined)
• new subaccount region (only required when new subaccount name is not empty )
• technical user credentials (usr/pswd pair or token is required)
• provider subaccount id (optional)
• btp backend url (optional, defaults to https://cli.btp.cloud.sap/)
• custom sap ias tenant's name (required)
• sap ias domain (optional, defaults to accounts.ondemand.com)
• kyma plan (required)
• kyma region (required)