docs: remove header and add notice

[sharathshivprasad]

• resolves TRG 7.07: Remove file header from md file and add NOTICE as post or preamble instead #94
• removed copyright header and updated notice section

[evegufy]

For readability of the file I'd add the notice at the end of the file (postamble)

I also don't understand the different years in the copyrighttext.

[adityagajbhiye9]

In ARC 42,Please check License header year.
It should be first year to last modified year.

[sharathshivprasad]

@evegufy @adityagajbhiye9 I have done the suggested changes. Can you please have a look at it? Thanks