Upgrade utf_16 project to use .NET 8 with NativeAot and remove runtime .NET dependency

[bhallasaksham]

Description of changes:

Upgrade utf_16 code to dotnet8 with NativeAot. This will remove the runtime dependency for dotnet.

Testing done:

• Tested on Ubuntu Open Source Mode
• Tested on Linux AL2023 Open Source Mode
• Tested on ECS non domain-joined mode

Created a new rpm (v1.3.65) and updated the rpm in ecs ec2 instance and linux ec2 instance. Verified that new tickets are being created in all modes.

Pending testing for renewals in Linux (AL2023) and ECS non domain-joined mode.

1.3.65 rpm size: 2.5MB
1.3.6 rpm size: 1.9MB

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[smhmhmd]

Thanks for making the change, this would remove the runtime dependency on dotnet.
2 changes as discussed:

1. Add Readme in the setup_scripts directory since there is similar logic in the docker dir as well.
2. Remove build-using-csc.sh and Program.runtimeconfig.json