IE 11 support

[aaka5h]

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report 
[ ] Performance issue
[x] Feature request
[ ] Documentation issue or request
[ ] Support request
[ ] Other... Please describe:

Current behavior

I see we are using tippy js which supports IE 11 with polyfills, currently helipopper is compiling for es2015.
can we compile it for es5 so that we can have support for IE (Why is IE immortal?).
At least app targeting es5 should compile with package installed as we are targeting es5 (functionality breaking are ok).
This will also require changes in @ngneat/overview

Angular version: 9.2

Browser:
- [ ] Chrome (desktop) version XX
- [ ] Chrome (Android) version XX
- [ ] Chrome (iOS) version XX
- [ ] Firefox version XX
- [ ] Safari (desktop) version XX
- [ ] Safari (iOS) version XX
- [X] IE version XX
- [ ] Edge version XX
 
For Tooling issues:
- Node version: 10.17.0
- Platform:  Windows