Nested config, devices registry

* All config now nested.
    - Use default config from model field default values. If providers
      should be enabled by default, non-empty default config file could
      be provided again.
    - Environment variable support with EOS_ prefix and __ between levels,
      e.g. EOS_SERVER__EOS_SERVER_PORT=8503 where all values are case
      insensitive.
      For more information see:
      https://docs.pydantic.dev/latest/concepts/pydantic_settings/#parsing-environment-variable-values
    - Use devices as registry for configured devices. DeviceBase as base
      class with for now just initializion support (in the future expand
      to operations during optimization).
    - Strip down ConfigEOS to the only configuration instance. Reload
      from file or reset to defaults is possible.

 * Fix multi-initialization of derived SingletonMixin classes.

src/akkudoktoreos/utils/visualize.py

@@ -34,7 +34,7 @@ class VisualizationReport(ConfigMixin):
         self.pdf_pages = PdfPages(filename, metadata={})  # Initialize PdfPages without metadata
         self.version = version  # overwrite version as test for constant output of pdf for test
         self.current_time = to_datetime(
-            as_string="YYYY-MM-DD HH:mm:ss", in_timezone=self.config.timezone
+            as_string="YYYY-MM-DD HH:mm:ss", in_timezone=self.config.prediction.timezone
         )
 
     def add_chart_to_group(self, chart_func: Callable[[], None]) -> None:
@@ -51,7 +51,7 @@ class VisualizationReport(ConfigMixin):
 
     def _initialize_pdf(self) -> None:
         """Create the output directory if it doesn't exist and initialize the PDF."""
-        output_dir = self.config.data_output_path
+        output_dir = self.config.general.data_output_path
 
         # If self.filename is already a valid path, use it; otherwise, combine it with output_dir
         if os.path.isabs(self.filename):
@@ -173,7 +173,7 @@ class VisualizationReport(ConfigMixin):
             plt.grid(True)
 
             # Add vertical line for the current date if within the axis range
-            current_time = pendulum.now(self.config.timezone)
+            current_time = pendulum.now(self.config.prediction.timezone)
             if timestamps[0].subtract(hours=2) <= current_time <= timestamps[-1]:
                 plt.axvline(current_time, color="r", linestyle="--", label="Now")
                 plt.text(current_time, plt.ylim()[1], "Now", color="r", ha="center", va="bottom")
@@ -419,7 +419,7 @@ def prepare_visualize(
     start_hour: Optional[int] = 0,
 ) -> None:
     report = VisualizationReport(filename)
-    next_full_hour_date = pendulum.now(report.config.timezone).start_of("hour").add(hours=1)
+    next_full_hour_date = pendulum.now(report.config.prediction.timezone).start_of("hour").add(hours=1)
     # Group 1:
     report.create_line_chart_date(
         next_full_hour_date,  # start_date