automatically select AMI for the intance type architecture

[tarunmenon95]

Added support for dynamic selection of architecture based on selected instance type

User is now prompted to select the service they would like to retrieve their AMI from based on those the chosen instance type supports.

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x86_64 example

1. User initiates a bastion launch with selected instance type of "c3.large", the user is then given the option to select the supported architectures for the instance type.

2) The user selects 'x86_64', they then choose the service where they want to pull the AMI from.

3) Finally, they select the AMI they would like to launch the bastion with, then continue on the with the normal workflow.

4) The bastion is launched with the selected AMI type.

---

arm64 example

1. Instance type supplied is 'c6g.large' which only supports arm64

2) We select our chosen AMI from our selected service.

3) The bastion is launches with the AMI using the selected architecture type

[tarunmenon95]

Refactored AMI to be selected automatically from selected instance type

• AMI's are now selected from predetermined SSM parameters
  

• We now find the supported architecture for the supplied instance type and return which SSM parameter to use as such.

for _, arch := range supported_architectures {
   	if *arch == "arm64" {
   		return "amazon-linux-arm64", nil
   	}
   	if *arch == "x86_64" {
   		return "amazon-linux", nil
   	}
   }

---

t3.micro (x86_64) example

• Bastion instance is launched with instance type 't3.micro' which only supports the 'x86_64' architecture.
  

• Created bastion instance is launched with auto-selected type of x86_64 as expected
  

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c6g.large (arm64) example

• Bastion instance is launched with instance type 'c6g.large' which only supports the 'arm64' architecture.
  

• Created bastion instance is launched with auto-selected type of arm64 as expected