Describe the change
Updates the Golang version of the frontend to 1.21.5, the latest version at the time of PR creation (1/03/2024) in the Dockerfiles of Fileshot, Filestream, Oneshot, Frontend, and Manager. Additionally, updated the go.mod file to reference the latest version of Golang and updated the module list to reflect the upgrade.

Describe testing procedures
All containers have been rebuilt locally and tested with a sample file with Strelka UI.

Sample output
N/A

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of and tested my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings