Update to determine sis enrollment sections

Changes for sections:

(1) SIS section id that matches the current course instance id, will appear first on the list.  

(2) SIS section id can be numeric only or pre-fixed with 'ci:'.  These are also known as cross-listed sections.

(3) "Primary" sections contain the above conditions (1) or (2) 

(4) Those sections with a sis section id that doesn't match the above conditions or do not have a sis section id, will appear after the primary section (or grouping or set)