Adds support for Unicode characters in database filenames.

[fdcastel]

Fix #11.

[fdcastel]

I removed the Unicode character from the filename to rule out any issues related to the GitHub environment's filesystem.

However, the error still persists.

I'll leave it removed for now and will revert it once the failing tests in the GitHub test environment are resolved.

[fdcastel]

I believe the issue is resolved, but the GitHub test environment still needs some adjustments.

On my build system, the new test passes:

# Invoke-Build FIREBIRD_DATABASE_can_create_database_with_unicode_characters ./image.tests.ps1

Build FIREBIRD_DATABASE_can_create_database_with_unicode_characters /opt/firebird-docker-fork/generated/4.0.5/bookworm/image.tests.ps1
Task /FIREBIRD_DATABASE_can_create_database_with_unicode_characters
Creating database '/tmp/próf-áêïôù.fdb'
Done /FIREBIRD_DATABASE_can_create_database_with_unicode_characters 00:00:05.8360229
Build succeeded. 1 tasks, 0 errors, 0 warnings 00:00:05.8389788

However, if I remove these two lines from the Dockerfile:

ENV LANG=C.UTF-8
ENV LC_ALL=C.UTF-8

The test fails.

[fdcastel]

✅ All set! All images are passing.

Solved the original issue with Unicode characters, as well as another one related to paths containing spaces.

Adds support for Unicode characters in database filenames.

• Adds environment variables for locale settings in Dockerfiles.
• Update database filename test for Unicode compatibility.
• Fix realpath call for paths with spaces.
• Adds test for databases with spaces in the path.
• Improves error message in tests if FULL_IMAGE_NAME env var is not set.
• Minor fix for ExitCodeIs.