Make the `col_width` customizable

[Anselmoo]

Is your feature request related to a problem? Please describe.

Make it possible to customize the width of the columns for printing larger proposed model names.

Describe the solution you'd like

def __init__(self, oracle, verbose=1): 
    ...

# change to

def __init__(self, oracle, verbose=1, col_width = 18):
    ...

Describe alternatives you've considered

Additional context

keras-tuner/keras_tuner/engine/oracle.py

Lines 118 to 122 in 417e5b5

	class Display(stateful.Stateful):
	def __init__(self, oracle, verbose=1):
	self.verbose = verbose
	self.oracle = oracle
	self.col_width = 18