Log process ID in each log entry (#949)

## Changes
This will help differentiate multiple cli commands that write to the
same log file.
Noticed that the root module wasn't using the common log utilities,
refactored it to avoid missing log arguments.
Relevant PR on the databricks vscode extension side:
databricks/databricks-vscode#923

## Tests
Tested manually for sdk and cli loggers

cmd/root/logger.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
+	"os"
 
 	"github.com/databricks/cli/libs/cmdio"
 	"github.com/databricks/cli/libs/env"
@@ -113,7 +114,7 @@ func (f *logFlags) initializeContext(ctx context.Context) (context.Context, erro
 		return nil, err
 	}
 
-	slog.SetDefault(slog.New(handler))
+	slog.SetDefault(slog.New(handler).With(slog.Int("pid", os.Getpid())))
 	return log.NewContext(ctx, slog.Default()), nil
 }