clean_raw: Clean extracted datasets
In QinglongYan/ANSSI: Automated near-stationary state identifier

This function is applied to filter datasets with low observation rate, long missing gap, impute missing values, and filter datasets with insufficient congestion periods

1	clean_raw(indir, outdir, obs = 0.95, hole = 3, tocc = 0.3, len = 5)

`indir`	The directory where the extracted datasets are located
`outdir`	The directory to save the preprocessed datasets
`obs`	Minimum acceptable observation rate
`hole`	Minimum acceptable hole size in minutes
`tocc`	Occupancy threshold
`len`	Minimum length of a congested period in minutes