FIO-8733: Update Docker build process

[brendanbond]

Link to Jira Ticket (if applicable)

https://formio.atlassian.net/browse/FIO-8733

Description

In an attempt to reduce the number of CVEs detected by Amazon Inspector, we've changed the base image from Ubuntu 24.04 to debian bookworm (12) slim. This means that:

• pdf2htmlEX still has to be compiled in Ubuntu and moved over
• some pdf2htmlEX dependencies must be cobbled together in the main image
• I've gone ahead and removed the chromium install, as pdf-libs has no need for it

Dependencies

n/a

How has this PR been tested?

n/a

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation (if applicable)
• My changes generate no new warnings
• My changes include tests that prove my fix is effective (or that my feature works as intended)
• New and existing unit/integration tests pass locally with my changes
• Any dependent changes have corresponding PRs that are listed above

[travist]

Tests are failing....