Refactor to_latex using polymorphism

Previously there was a complicated logic in multiple methods
for either longtable or regular table.

This commit implements
 - ``LatexTableFormatter``,
 - ``LatexTabularFormatter``,
 - ``LatexLongTableFormatter``,
derived from ``LatexFormatter``, based on ``LatexFormatterAbstract``.

Each of the derived classes implements its own methods for writing
 - beginning of the table;
 - caption and labels;
 - separators;
 - end of the table.

LatexFormatter changes
----------------------

 - Make the process of creating tables more readable.
 - Drop escape and bold_rows attr

Author: ivanovmg

pandas/io/formats/format.py

@@ -936,19 +936,35 @@ def to_latex(
         """
         Render a DataFrame to a LaTeX tabular/longtable environment output.
         """
-        from pandas.io.formats.latex import LatexFormatter
-
-        return LatexFormatter(
-            self,
-            column_format=column_format,
+        latex_formatter = self._create_latex_formatter(
             longtable=longtable,
+            column_format=column_format,
             multicolumn=multicolumn,
             multicolumn_format=multicolumn_format,
             multirow=multirow,
             caption=caption,
             label=label,
             position=position,
-        ).get_result(buf=buf, encoding=encoding)
+        )
+        return latex_formatter.get_result(buf=buf, encoding=encoding)
+
+    def _create_latex_formatter(self, **kwargs):
+        """Create concrete instance of LatexFormatter."""
+        from pandas.io.formats.latex import (
+            LatexLongTableFormatter,
+            LatexTableFormatter,
+            LatexTabularFormatter,
+        )
+
+        is_longtable = kwargs.pop("longtable")
+        is_table = any(
+            [kwargs.get("caption"), kwargs.get("label"), kwargs.get("position")]
+        )
+        if is_longtable:
+            return LatexLongTableFormatter(self, **kwargs)
+        if is_table:
+            return LatexTableFormatter(self, **kwargs)
+        return LatexTabularFormatter(self, **kwargs)
 
     def _format_col(self, i: int) -> List[str]:
         frame = self.tr_frame