feat: add fixed electricity prediction with time window support (#930)

Add a fixed electricity prediction that supports prices per time window.
The time windows may flexible be defined by day or date.

The prediction documentation is updated to also cover the ElecPriceFixed
provider.

The feature includes several changes that are not directly related to the
electricity price prediction implementation but are necessary to keep
EOS running properly and to test and document the changes.

* feat: add value time windows

    Add time windows with an associated float value.

* feat: harden eos measurements endpoints error detection and reporting

    Cover more errors that may be raised during endpoint access. Report the
    errors including trace information to ease debugging.

* feat: extend server configuration to cover all arguments

    Make the argument controlled options also available in server configuration.

* fix: eos config configuration by cli arguments

    Move the command line argument handling to config eos so that it is
    excuted whenever eos config is rebuild or reset.

* chore: extend measurement endpoint system test

* chore: refactor time windows

    Move time windows to configabc as they are only used in configurations.
    Also move all tests to test_configabc.

* chore: provide config update errors in eosdash with summarized error text

    If there is an update error provide the error text as a summary. On click
    provide the full error text.

* chore: force eosdash ip address and port in makefile dev run

    Ensure eosdash ip address and port are correctly set for development runs.

Signed-off-by: Bobby Noelte <b0661n0e17e@gmail.com>

docs/akkudoktoreos/prediction.md

@@ -123,10 +123,12 @@ Configuration options:
 
     - `ElecPriceAkkudoktor`: Retrieves from Akkudoktor.net.
     - `ElecPriceEnergyCharts`: Retrieves from Energy-Charts.info.
+    - `ElecPriceFixed`: Caluclates from configured time window prices.
     - `ElecPriceImport`: Imports from a file or JSON string.
 
   - `charges_kwh`: Electricity price charges (€/kWh).
   - `vat_rate`: VAT rate factor applied to electricity price when charges are used (default: 1.19).
+  - `elecpricefixed.time_windows.windows`: The time windows with associated electricity prices.
   - `elecpriceimport.import_file_path`: Path to the file to import electricity price forecast data from.
   - `elecpriceimport.import_json`: JSON string, dictionary of electricity price forecast value lists.
   - `energycharts.bidding_zone`: Bidding zone Energy Charts shall provide price data for.
@@ -142,12 +144,12 @@ option are added.
 ### ElecPriceEnergyCharts Provider
 
 The `ElecPriceEnergyCharts` provider retrieves day-ahead electricity market prices from
-[Energy-Charts.info](https://www.Energy-Charts.info). It supports both short-term and extended forecasting by combining
-real-time market data with historical price trends.
+[Energy-Charts.info](https://www.Energy-Charts.info). It supports both short-term and extended
+forecasting by combining real-time market data with historical price trends.
 
 - For the next 24 hours, market prices are fetched directly from Energy-Charts.info.
-- For periods beyond 24 hours, prices are estimated using extrapolation based on historical data and the latest
-  available market values.
+- For periods beyond 24 hours, prices are estimated using extrapolation based on historical data
+  and the latest available market values.
 
 Charges and VAT
 
@@ -157,6 +159,11 @@ Charges and VAT
 
 **Note:** For the most accurate forecasts, it is recommended to set the `historic_hours` parameter to 840.
 
+### ElecPriceFixed Provider
+
+The `ElecPriceFixed` provider calculates the day-ahead electricity market prices from the configuration
+of electricity price time windows set up by the user.
+
 ### ElecPriceImport Provider
 
 The `ElecPriceImport` provider is designed to import electricity prices from a file or a JSON