Enable builder pattern for various types of tables

This reverts ``pandas/io/formats/format.py``
to its nearly original state and enables polymorphism
under the hood inside ``pandas/io/formats/latex.py``.

Add ``pandas/tests/io/formats/test_latex.py`` to test
lower-level functions/classes declared in
``pandas/io/formats/latex.py``

Author: ivanovmg

pandas/io/formats/format.py

@@ -936,7 +936,10 @@ def to_latex(
         """
         Render a DataFrame to a LaTeX tabular/longtable environment output.
         """
-        latex_formatter = self._create_latex_formatter(
+        from pandas.io.formats.latex import LatexFormatter
+
+        latex_formatter = LatexFormatter(
+            self,
             longtable=longtable,
             column_format=column_format,
             multicolumn=multicolumn,
@@ -948,24 +951,6 @@ def to_latex(
         )
         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
         formatter = self._get_formatter(i)