Parameters from config file will be added at --cfg options location to
be processed

Config file example:
 #ignore comment
 ext-partition   : 1 #ignore as well
 codec           : av1
 psnr            : ON

Note(s):
    - Config file is a simple text file
    - Comment starts with hash(#)
      Can be full line or part of the line, after hash(#) details are
ignored
    - Format: field : value
      colon(:) as delimeter, otherwise full line will be ignored
      Space(s) and tab(s) can be used, not inside field
    - long names for field are prefered
       existing --long_name option format
    - "no value" fields should contain ON as value

Example of usage:
    aomenc --cfg=some.cfg src_filename

Configurations support matrix:
enable-ext-partition         : done
enable-loop-restoration      : wip
enable-deblocking            : wip
...

Change-Id: Iad867c5d2da64271cdafa825c89f7d6444582f61