REFACTOR: Simplify converter steps in migration tooling (#29779)

* Remove unused `report_progress_in_percent` option from step
* Remove `use_custom_progress_increment` option from the step because we can figure it out by looking at the progress
* Introduce `StepTracker` to for logging warnings and errors and tracking step progress
* Make it easier to log warnings and errors in all methods of `Step` without the need to pass around a `stats` object

migrations/lib/converters/base/step_tracker.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module Migrations::Converters::Base
+  class StepTracker
+    attr_reader :stats
+
+    def initialize
+      @stats = StepStats.new
+      reset_stats!
+    end
+
+    def reset_stats!
+      @stats.progress = 1
+      @stats.warning_count = 0
+      @stats.error_count = 0
+    end
+
+    def progress=(value)
+      @stats.progress = value
+    end
+
+    def log_info(message, details: nil)
+      log(::Migrations::Database::IntermediateDB::LogEntry::INFO, message, details:)
+    end
+
+    def log_warning(message, exception: nil, details: nil)
+      @stats.warning_count += 1
+      log(::Migrations::Database::IntermediateDB::LogEntry::WARNING, message, exception:, details:)
+    end
+
+    def log_error(message, exception: nil, details: nil)
+      @stats.error_count += 1
+      log(::Migrations::Database::IntermediateDB::LogEntry::ERROR, message, exception:, details:)
+    end
+
+    private
+
+    def log(type, message, exception: nil, details: nil)
+      ::Migrations::Database::IntermediateDB::LogEntry.create!(
+        type:,
+        message:,
+        exception:,
+        details:,
+      )
+    end
+  end
+end