Allow to use custom DataFrame index and column names

[KIC]

Usually, the DataFrames have the "time" in the index. This means we always have to do something like:

df.reset_index().rename(columns={"Date": "time", "Open": 'open', "High": 'high', "Low": 'low', "Close": 'close'}),

I think some heuristics could help:

1. check if the index is of type Timestamp -> use as x
2. check if any other column is of type Timestamp -> use as x

Something similar should be used for the marks, i.e. use the first 4 columns for candles and the first one for a line.

At least as a user I should be able to conveniently declare my column names/index which should be used I think.

Nevertheless, I think using lightweight charts with python (notebooks) will greatly improve financial plots over mplf, plotly and others.