Closes #1063

This PR partially implements inheritance of configuration file from proposal #1063
Configuration profile is loaded based on default_profile: ...... field and this profile is the only profile that must be properly configured.
Following logic is implemented for loading configuration of profile:

• user defined default_profile is loaded based on provided configuration file, if entry does not exist error will be emmited and default value providede by contour will be used
• each profile in the configuration file inherits all values from default_profile and if some of the field is provided inside configuration provided value for this profile will be used

example:

profiles:
    main:
.......................
    inher:
        shell: "/usr/bin/bash"
        history:
            limit: 0

Inheritance also implemented for color chemes with the only difference that color_schemes.default is always used as default color chemes and must be properly configured