Let workspace private and personal by default for all user

[hghandri]

Issue: #227

Implement private workspace, every user create a workspace now is only private and not shareable with other user.
This feature implement a new DynamoBD table handle policies on top of Workspace Dynamodb table.
This implementation could facilitate sharing workspaces between users with writeable / readable policy option through sharing process like Google Drive

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[massi-ang]

Thanks for submitting this PR. Is this changing all Workspaces to private to the user?

[hghandri]

Yes by default, all workspace will be private.
If we go ahead of this feature we could add interface to set if we want to open publicly the workspace or for some people ( example fetch a user from cognito )

[massi-ang]

As this is a breaking change, we should either think about an opt-in/out settings or the possibility to set workspaces as public/private and retain all existing workspaces as public.

[hghandri]

Hi,

yes this cause with my actual version a breaking change.
I will try to introduce a "Public" property we could set through workspace creation workflow.
In this case we could set arbitrary all existing workspace as Public with this property to handle a legacy behaviour.

In further with this feature the concept was to allow any user with he is private workspace could easily share he is workspace with other user or group of user. Thats why I've implemented a new DynamoDB table to handle permission.

++

[hghandri]

I closed this PR and opened a new one with more impact.