Feature/add device breakpoints

[amitchawla22]

@sheikalthaf @iamlothian
I have added support for customizing breakpoints for ngx-carousel as i had a specific requirement in the project, So it can be with others as well, for e.g. my sm break point was at 600px and md break point was at 1024 px and lg at 1440px. So if anyone having this kinda requirement can easily with this pr. Please review and let me know in case of any issues.

Implmented changes:

• Extended existing interface to add breakpoints for customization
• Added logic to customize the breakpoints and usage
• Added breakpoint in demo
• Updated documentation in README.MD

[asenmitrev]

Perfect, exactly what I need for my project. Code seems to be OK as well.

[amitchawla22]

@DedoGospod Thanks for liking it, May you please help me with the areas where i need to improve on this logic for the PR to be merged

[amitchawla22]

@sheikalthaf @iamlothian May you please help me to merge this code base in your master branch, So that everyone can use it if required, it is just a minor enhancement but very useful though.

[sheikalthaf]

Hi @amitchawla22 ,
I really want to merge your code into my master branch but I need to verify your code. once I reviewed your code I will merge your code

[sheikalthaf]

Hi @amitchawla22 ,
This carousel is depreciated.
I'm not maintaining this carousel instead I'm actively using @ngu/carousel. please check this repo ngu-carousel and make your pull request their so that i can verfiy.
I love the idea on your pull request
I'm sorry for the depreciation