Improve parsing and validation of ColorSpace for inline image

This ticket is a follow-up of PDFBOX-3235.

Currently neither Preflight, nor PDModel checks the following restrictions of ColorSpace for inline image (as defined in PDF Reference 1.4 and ISO 32000):

• if Indexed color space specified, its color table must be specified by a byte string;
• abbreviations used for the names of color spaces are valid only in inline images.

PDModel and Preflight should check and validate that color table of Indexed table is string and support the abbreviated names of color space only within the content stream of inline image.