Make `dateRange` and `dateRound` coherent

[Byloth]

Right now, dateRange and dateRound functions aren't coherent when it comes to weeks, months or years.

Here's an example of generated dates:

[
    "2024-09-03",
    "2024-10-03",
    "2024-11-02",
    "2024-12-02",
    "2025-01-01",
    "2025-01-31",
    "2025-03-02",
    "2025-04-01",
    "2025-05-01",
    "2025-05-31",
    "2025-06-30",
    "2025-07-30",
    "2025-08-29"
]

... on the other hand, it should work like:

[
    "2024-09-01",
    "2024-10-01",
    "2024-11-01",
    "2024-12-01",
    "2025-01-01",
    "2025-02-01",
    "2025-03-01",
    "2025-04-01",
    "2025-05-01",
    "2025-06-01",
    "2025-07-01",
    "2025-08-01",
    "2025-09-01"
]