Remove legacy logging infrastructure

[Sakeeb91]

Summary

• delete the legacy Logging infrastructure from FlowCtl.Infrastructure
• drop the unused LoggerExtensions helper that depended on those types
• remove the csproj exclusions that referenced the folder so the project stays tidy

Design Decisions & Rationale

• the custom console logger was unused and already excluded from build; removing it prevents dead code and clarifies which logging pathway the CLI actually supports
• removing LoggerExtensions avoids stale references to deleted types and keeps future cleanups straightforward
• trimming the Compile Remove entries keeps the project file aligned with the files that remain in source control

Tests

• dotnet test FlowCtl.sln
• dotnet format --verify-no-changes FlowCtl.sln --include src/FlowCtl.Infrastructure/FlowCtl.Infrastructure.csproj

Alignment with Repository Patterns & Objectives

• simplifies the infrastructure layer to only include actively supported services, matching the repo's emphasis on lean CLI components
• ensures all code paths that remain map to the newer Spectre console–based logger used by the application
• reduces maintenance surface area ahead of future releases without altering runtime behavior

Closes #117.

[ziagham]

Nice clean-up