Added fallback for profile pics.

[OmkarPh]

Added fallback image for profile pic in people's page as I said https://github.com/LoginRadius/cascade/issues/4#issuecomment-701412740

Fixed #4.

Changes proposed in the pull request:

• Added onError event listener in Usercard and People components
• Added setAlternative() for auditing source when error occurs i.e. image couldn't be loaded

Risk Impact

• The function setAlternative() might be in inappropriate position considering your codebase, but it is fully working, and you can shift or modify it's position if necessary

Please tell me if I have done something which is not recommended or not advisable :)

@mohammed786

[OmkarPh]

Can anybody have a look at this PR...

[OmkarPh]

Hi @mohammed786 I saw hacktoberfest guidelines today and it said repo has to add "hacktoberfest" topic to their repos for counting into hacktoberfest, but on this cascade repo that topic is misspelled as "hactoberfest"

Can you rectify it :-)