Add Global Setting for Start Instance Default

Add Global Setting for Start Instance Default

##### ISSUE TYPE

* Enhancement Request

##### COMPONENT NAME

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UI
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##### CLOUDSTACK VERSION

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4.19.1.1
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##### CONFIGURATION

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N/A
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##### OS / ENVIRONMENT

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KVM
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##### SUMMARY

We would like to change the default behavior at instance creation for some use cases we have. This Enhancement would add the ability to change that behavior if someone wanted to. A global setting would accomplish this and let the default out of the box still be Start by default.

##### STEPS TO REPRODUCE

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N/A - Workflow Enhancement
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##### EXPECTED RESULTS

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Global Setting that would change the default behavior of Start Instance from `Yes` to `No`. The Global setting would be set to `Yes` by default.
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##### ACTUAL RESULTS

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Default is hard coded to Start Instance at instance creation.
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先找出執行個體建立路徑和現有的全域設定定義；issue 未指定特定的檔案或測試。完成的標準是：某個全域設定預設為 Yes，允許將 Start Instance 的預設行為改為 No，並在未變更時保留目前開箱即用的行為。

由索引模型根據 Issue 內容生成。