Add datetime axis capability to categorical plots

#### Is your feature request related to a problem? Please describe.
This issue was first raised here: https://discourse.holoviz.org/t/workaround-for-date-based-histogram-tick-labels/788

I have time series data, and would like to bin the data according to different time resolutions.
When I try linking axes and controlling axis tick labels, I find it difficult to do so:

```
import numpy as np
import pandas as pd

import hvplot.pandas
import holoviews as hv
from bokeh.models.formatters import DatetimeTickFormatter

# Create data frame
days = pd.date_range(start=pd.to_datetime('2001-01-01'), end=pd.to_datetime('2001-12-31'))
ncols = 5
columns = np.arange(ncols) + 1
data = np.random.rand(365, ncols)
df = pd.DataFrame(data, index=days, columns=columns)
df.index.name = 'time'

# Determine number of days where row mean is above 0.5
mean_above_midpoint = (df.agg('mean', axis=1) > 0.5).astype(int)
df['days_above_midpoint'] = mean_above_midpoint
df_weekly = df.resample('W').mean()
df_weekly['days_above_midpoint'] = df['days_above_midpoint'].resample('W').sum()
df_weekly.head()

formatter = DatetimeTickFormatter(months='%b')
columnLabels = [str(x) for x in columns]

lines = df_weekly.hvplot.line(x='time', y=columnLabels, title='Measurements', xformatter=formatter)
hist = df_weekly.hvplot.bar(x='time', y='days_above_midpoint', title='Days Above Midpoint', xformatter=formatter)

(lines + hist).cols(1)
```

#### Describe the solution you'd like
Most categorical plots (histogram, box+whisker, violin) have utility when the bins are discrete time intervals, rather than categories. It would be nice if these plots allowed a datetime axis with all of the related linking abilities to other time series plots.

I am aware now of a workaround using Holoviews, but it's not something I could have figured out on my own.

Thanks for your consideration!