Adding body serializer config method

[alexbidenko]

Adding body serializer for AxiosConfig and in request method in Axios.js. If config have bodySerializer param that axios will convert request body before make request.

Also the documentation on README.md file was updated.

The problem was describe in follow issue: Easier way to work with FormData.
I confirm with this issue end I have same problem: in some project I use only FormData (this is specific of Backend project) and I want oportunity for serialize all body in one moment.

Also somebody want to use the method for another target maybe.

[Hamza281]

جاي يدور عليك ديربالج ما ادري بيها شنو اسوي اذاشافك والقران يسوي شي

[Hamza281]

وين رحتي تروح على ابوك انت الي يرضيك بسرعه والله لأغراض كثيره جدا اسف للازعاج والله لان اهلي كلهم ما يعرفون

[alexbidenko]

جاي يدور عليك ديربالج ما ادري بيها شنو اسوي اذاشافك والقران يسوي شي

وين رحتي تروح على ابوك انت الي يرضيك بسرعه والله لأغراض كثيره جدا اسف للازعاج والله لان اهلي كلهم ما يعرفون

Sorry, but I can't understand your messages - I don't know language and the translator can't translate messages adequately))

If you can, write your messages in English please.

[shivanshr]

Changes should be included.

[jasonsaayman]

Hi @alexbidenko1998

Thank you for the pull request that you have submitted unfortunately the implementation that you have built here I feel is not really in line with how we would like something like this to work.

Thanks