(ref + fix): Moving ZeSlotConfiguration persistence logic to a repository

[lucasvillaverde]

Summary

• Extracting the logic from ZePersistence, which handled theme, open api and zeslot rules to a ZeSlotRepository;
• With this approach we can use this repository across screens and possibly detach current features to use their own VM (such as the simulator screen);
• Also enables (if needed) to change how the data is retrieved, we can change it to a flow and shift to observable pattern for example;
• As a bonus, this fixes Fixes #395, since it enables us to add and remove previously saved configurations.

How It Was Tested

Screenshot/Gif

Reset fix	Overall behavior

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