add keycloak - initial

[abhinavkrin]

This PR will add keycloak to RC4Community.

[Sing-Li]

This is awesome. @debdutdeb can you please update our keycloak server and let's get community.rocket.chat working with REAL AUTH. (just can't wait to see the linkage with superprofile - hint Ronlek ;-) )

[Sing-Li]

@abhinavkrin please advise if this is good enough to merge for our upcoming Alumni Summit purpose

[Sing-Li]

Please also make keycloak the default IDM provider (if possible) for RC4Community instead of Firebase.

I've checked out the ISC license. Totally OK to include. Thanks.

[abhinavkrin]

Please also make keycloak the default IDM provider (if possible) for RC4Community instead of Firebase.

I've checked out the ISC license. Totally OK to include. Thanks.

It's fine to merge this PR. The default IDM would be keycloak.
Currently.
The user will have the following attribute:

1. id
2. our custom access token
3. image
4. name
5. email

[Sing-Li]

Please remove package-lock.json from the PR (and perhaps add it to your .gitignore) - thanks. @abhinavkrin

[abhinavkrin]

Please remove package-lock.json from the PR (and perhaps add it to your .gitignore) - thanks. @abhinavkrin

Removed package-lock.json @Sing-Li