Implement hscdata module.

The module will help users access database in Jupyter environment.

It consists of the following submodules.

• Image cut out sub-module
  This module is for cutting out image from the reduced data.
  The usage of it will be something like this:
  hscdata.image.cutout(ra=150, dec=2, size='1arcsec', filter='HSC-I') => cut out image

• Psf picker sub-module
  This module is for retrieving PSF image or model from the reduced data.
  The usage of it will be something like this:
  hscdata.psf.pick(ra=150, dec=2, filter='HSC-I') => PSF Image or PSF Model

• File search sub-module
  This module is for searching and retrieving the reduced data.
  The usage of it will be something like this:
  results = hscata.fileSearch.findCoadd(ra=150, dec=2, size='1arcsec', filter='HSC-I') => astropy.HDUList
  print(results[0].fileName) => '/somewhere/coadd-123.fits' # the file is mounted in compute environment.

• SQL sub-module
  This module is for throwing SQL and retrieving resultant records from the Postgres database.
  The usage of it will be something like:
  object_id, mag = hscdata.sql.asNumpy('select object_id, imag_kron  from s18a_wide.forced limit 10' )
  object_id._class_ => numpy.ndarray
  mag._class_ => numpy.ndarra