Improvement: Parse grouped by dates automatically

[timo-at-lanalabs]

Currently the data that arrives from a request like this:

df = api.aggregate(log_id, metric="frequency", grouping="byMonth",  
                   date_type="startDate", max_amount_attributes=10000)

is ordered by the frequency. The grouped by column is returned as string and not natively recognized by python. The quarterly string needs parsing. Ideally we centralise this function in PyLana.

if "byQuarter" in df.columns:
    df['x_axes'] = pd.to_datetime(
        df['byQuarter'].str.replace(r'(Q\d) (\d+)', r'\2-\1'), errors='coerce')
elif "byYear" in df.columns:
    df["x_axes"] = pd.to_datetime(df.byYear)
elif "byMonth" in df.columns:
    df["x_axes"] = pd.to_datetime(df.byMonth)