Fixes on phase 2

[abdelazizElemary]

• fix padding and spaces in the header navbar.
• fix spaces between courses
• enable grouping of courses with category type when selecting category
• fix fonts and color all over the page
• make the search with include() not the exact keyword

[EmilMourad]

points 1 , 2 , 4 and 5 are fixed . Regarding point 3 , it will be available in phase 3.