GD-272: C# - Complete c# tools

[MikeSchulze]

Description

At gd-script api we support a set of tools to make the live easier. Add missing tools for c# https://mikeschulze.github.io/gdUnit3/advanced_testing/tools/

Acceptance criteria

• ErrorAsString -> https://mikeschulze.github.io/gdUnit3/advanced_testing/tools/#error_as_string
• CreateTempFile -> https://mikeschulze.github.io/gdUnit3/advanced_testing/tools/#create_temp_file
• ResourceAsArray/ResourceAsList -> https://mikeschulze.github.io/gdUnit3/advanced_testing/tools/#resource_as_array
• ResourceAsString -> https://mikeschulze.github.io/gdUnit3/advanced_testing/tools/#resource_as_string