Side Navigation // re-make component (CSS only) (#541)

* rebase

* add line-height to ensure all nav items are the same height

both with and without icons

* button expand/collapse (with RTL support)

* simplify

* simplify, and add some notes

* button a11y

* add some examples, update notes

* add `.active`

* add active, fix height issues, fix disabled colors

* add notes

* fix hover color on anchor tags

* update chevrons

* update notes

* fix chevron color

* add "trail" styling

* format

* notes and formatting

* simplify

* RTL support

* don't erase the icon on hover

* simplify

* better note

* typo

* notes

* notes

* add multilevel example without icons

* update snapshots

* fix a bug

* add notes

* truncation

* touchup

* typos

* one more bug in the truncation ish

* *sigh* gotta use more `<span>`s... *siiiiiigh*

* code cleanup

* add more examples

* update snapshots

* cleanup examples

and update snapshots

* update notes, update changelog

* formatting

* formatting

* simplify via Enrique's suggestion

* fix a11y issues

* more a11y fixes

* remove completed todo

* fix the excess padding for truncated text issue

* fix the spacing between icons (12px -> 8px)

* force proper font-family

* fix a11y issues

* fix height issue

* update snapshots

* fix a11y issue

* updated changelog

css-library/neo/changelog.md

@@ -1,5 +1,11 @@
 # Changelog
 
+### 3.81.22
+
+### New Features - Recently Added
+
+- Add Side Navigation (NEO-2403)
+
 ### 3.81.21
 
 ### New Features - Recently Added