docs(nx-cloud): add to launch templates documentation (#23156)

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## Current Behavior
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launch template docs are pretty sparse

## Expected Behavior
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expand upon what you can do with a custom launch template with some
examples

## Related Issue(s)
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merged. -->

contributes to: APP-1414

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Co-authored-by: Altan Stalker <[email protected]>

Author: barbados-clemens