[SPRAW-60] Update CourseTopNav component to new design

[myslaf]

Add new icons.
Change existing icons to new from design.
Update Button mode types.
Add new gray button.

[github-actions]

AXE a11y errors violations

4 accessibility violations were detected

id	impact	description	nodes
aria-command-name	serious	Ensures every ARIA button, link and menuitem has an accessible name	3
color-contrast	serious	Ensures the contrast between foreground and background colors meets WCAG 2 AA minimum contrast ratio thresholds	2
label	critical	Ensures every form element has a label	2
nested-interactive	serious	Ensures interactive controls are not nested as they are not always announced by screen readers or can cause focus problems for assistive technologies	2