Add Bengali translation of code-of-conduct

[ayan-b]

Related to #1

[shakib609]

Translate the whole portion in a single line otherwise it's quite hard to review further.

[ayan-b]

Translate the whole portion in a single line otherwise it's quite hard to review further.

I do not really know the style guide followed here, but it is, in general, a good idea to follow an 80 character limit for a single line (ref). Let me know if it is followed here or not.

In the English files, it is not followed. I will translate a whole paragraph in a single line. Thanks!

[ayan-b]

@nutboltu @shakib609 Please review and let me know if something needs changing.

[nutboltu]

despite some spacing issue, looks good!
Good work @ayan-b

[ayan-b]

@shakib609 Please review and let me know something needs to be changed.

[shakib609]

Looks good. Merging.
Great work!

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