Animations on opening & closing left side-nav

### Issue type

**I'm submitting a ...** (check one with "x")

* [ ] bug report
* [x ] feature request
* [ ] question about the decisions made in the repository

### Issue description

**Current behavior:**
There is no animation added on left side nav

**Expected behavior:**
Left Side Nav should have animation on opening & closing

**Steps to reproduce:**
1- Open & close left side nav

### Other information:
I would like to contribute in this issue.