Add a landing page for the server

[Shivam010]

A landing page is required, as of now the server only works as an API.
The root path, / requests should route to the landing page and rest all request should be routed to use the current handler of the API.

Currently, https://non-cors.herokuapp.com/ returns StatusPreconditionFailed error

{
  "error": {
    "Code": 412,
    "Message": "URL not provided",
    "Detail": {
      "method": "GET",
      "requestedURL": "/"
    }
  }
}

but instead should be route to a landing page describing the bypass-cors server.

Suggestion: README.md file can be utilized to create the landing page.

[0xsubi]

@Shivam010 I have kept it as small as possible.
#8

[Shivam010]

@sudhabindu1 Check the requested changes in the PR review.

[vakhariaheet]

@Shivam010 Can I try it?

[Shivam010]

@heet-vakharia
Sure, you are most welcome.

Quick note: Try to utilize the README.md file

[vakhariaheet]

ok, Thank you

[Shub3am]

is anyone working on this?