feature: instance boot group and readiness (#677)

* feature: instance boot group and readiness

Related https://github.com/apache/cloudstack/pull/13907

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

* address comments and changes

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

* add screens

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

* more comment

Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>

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Signed-off-by: Abhishek Kumar <abhishek.mrt22@gmail.com>