Custom collapse breakpoint feature

[BranislavMateas]

Hello everyone! So basically, I was using your package in my project, but I ran into this problem so I thought and told myself that it would be great to have the ability to set the custom breakpoint, when will our menu collapse. And so, I delivered. Hope you like it (and merge it 😁).

Signed by Branislav Mateáš.

[Jamalianpour]

Hello and thank you,
Can you change the name of sideMenuBreakpoint? I thinks that's a little confusing.
And don't use sideMenu in name.

[BranislavMateas]

I think the collapseWidth might be less confusing. Better?