chore: remove unused methods

unused? avoid using because it is not intuitive? complicates
things?

Refs: ECALC-1830

src/ecalc_cli/io/output.py

@@ -151,9 +151,12 @@ def export_tsv(
     prognosis_filter = config.filter(frequency=frequency)
     result = prognosis_filter.filter(ExportableGraphResult(results), resampled_periods)
 
-    row_based_data: dict[str, list[str]] = CSVFormatter(
-        separation_character="\t", index_formatters=PeriodFormatterConfig.get_row_index_formatters()
-    ).format_groups(result)
+    row_based_data: dict[str, list[str]] = {
+        key: CSVFormatter(
+            separation_character="\t", index_formatters=PeriodFormatterConfig.get_row_index_formatters()
+        ).format(val)
+        for key, val in result.items()
+    }
 
     exporter = Exporter()
     exporter.add_handler(

src/libecalc/presentation/exporter/formatters/formatter.py

@@ -1,6 +1,6 @@
 import abc
 
-from libecalc.presentation.exporter.formatters.formattable import Formattable, FormattableGroup
+from libecalc.presentation.exporter.formatters.formattable import Formattable
 from libecalc.presentation.exporter.formatters.index_formatter import IndexFormatter
 
 
@@ -13,9 +13,6 @@ def format(self, table: Formattable) -> list[str]:
         """
         ...
 
-    @abc.abstractmethod
-    def format_group(self, groups: FormattableGroup) -> dict[str, list[str]]: ...
-
 
 class CSVFormatter:
     def __init__(self, separation_character: str = ",", index_formatters: list[IndexFormatter] = None):
@@ -42,9 +39,3 @@ def format(self, tabular: Formattable) -> list[str]:
             row = [str(tabular.get_value(row_id, column_id)) for column_id in column_ids]
             rows.append(self.separation_character.join([*row_index, *row]))
         return rows
-
-    def format_groups(self, grouped_tabular: FormattableGroup) -> dict[str, list[str]]:
-        csv_formatted_lists_per_installation: dict[str, list[str]] = {}
-        for group_name, tabular in grouped_tabular.groups:
-            csv_formatted_lists_per_installation[group_name] = self.format(tabular)
-        return csv_formatted_lists_per_installation