feat: add flexmeasures add schedule generic command

[victorgarcia98]

Description

In order to make the testing of new schdulers easier, this PR introduces the command flexmeasures add schedule generic. This command gets a Scheduler class name as one of its inputs and allows create/edit the flex-model and flex-context using your default editor (e.g vim, vscode, pycharm, ...).

How it looks

Prerequisites

• Sensor to store the results of the schedule (in the example, ID=1)
• Sensor with cost data (ini the example ID=2)

Beware, you require to have data in the planning window, in this example, (2023-01-01 00, 2023-01-01 12).

1. Run the command to add a new schedule:

flexmeasures add schedule generic --sensor-id 1 --scheduler ShiftableLoadScheduler  --start 2023-01-01T00:00:00+01:00 --duration PT12H --edit-flex-model

2. Your default editor will open. Input the following flex-model and save:

{"cost-sensor": 2, "duration": "PT5H", "load-type": "INFLEXIBLE","power": 2.0}

3. Show the resulting schedule:

flexmeasures show beliefs --sensor-id 1 --start 2023-01-01T00:00:00+01:00 --duration PT12H

[victorgarcia98]

Closing this in favor of creating custom commands for the schedules.