chore: update dependencies

[melton-jason]

Fixes #34, #26
Might fix #9 (included in testing instructions. I did my own testing and did not run into any errors: it would appear that ImageMagick fixed their default policy.xml).
Includes required packages for #38 (see related #36)

This PR seeks to:

• update many old/outdated components of the web asset server
• Include the boto3 package, which is required to implement Merge exoscale-assets and s3-commands branches into a unified branch with environment-specific settings #38
• add a sample docker-compose.yml

A list of updated and installed software for this PR is provided below:

Library / Software	Old Version	New Version	Old Version Notes	New Version Notes
Ubuntu	18.04	22.04	EOL May 2023	EOL Apr 2027
Python	3.6	3.12	EOL Dec 2023	(Latest Security) EOL Oct 2028
ExifRead	2.3.1	3.5.1	Released Aug 7, 2020	(Latest) Released Aug 23, 2025
Paste	3.4.4	3.10.1	Released Sep 9, 2020	(Latest) Released May 1, 2024
sh	1.14.0	2.2.2	Released Aug 28, 2020	(Latest) Released Feb 24, 2025
Bottle	>=0.12.23,<=0.13	>=0.12.23,<=0.13	(0.12.25) Released Mar 4, 2023
boto3	-	>=1.26.0,<2.0		(1.40.46) Released Oct 6, 2025

Testing Instructions:

• Ensure functionality/consistency across all endpoints described in web_asset_server.xml
  • fileget
  • fileupload
  • filedelete
  • getmetadata
  • testkey
• For (ImageMagick update breaks PDF thumbnailing. #9), specifically test the above endpoints with PDF files, and ensure no error is raised