feat: TxtFormatterCrlf for raw-mode console line endings (#269)

[victoriacampbellmake]

Summary

Adds optional CRLF line endings for TxtFormatter so raw-mode consoles reset the cursor to column 0 (#269).

Bare \n leaves the cursor in the same column on some raw terminals. File appenders can already normalize EOL via NativeEOLConverter; this covers console / raw output where the formatter's trailing newline is what the terminal sees.

Changes

• TxtFormatterImpl gains a useCrlf template parameter (default false, existing behavior unchanged)
• New aliases: TxtFormatterCrlf, TxtFormatterUtcTimeCrlf

Usage:

plog::ConsoleAppender<plog::TxtFormatterCrlf> appender;

Closes #269