Deny users to create organization with name that is url incompatible or reserved

[sleshchenko]

Organization name should be the same as its organizational account's name. So it will be used to access to workspace in urls like protocol://host/accountName/workspaceName
As result it is need to deny users to create organization with name that is url incompatible or reserved to avoid issues of access to workspaces.

These kind of checks already are implemented for user's name.
https://github.com/codenvy/codenvy/blob/jpa-integration/wsmaster/codenvy-hosted-sso-server-organization/src/main/java/com/codenvy/auth/sso/server/OrgServiceUserValidator.java#L69-71
https://github.com/eclipse/che/blob/jpa-integration/wsmaster/che-core-api-user/src/main/java/org/eclipse/che/api/user/server/UserManager.java#L86-88

[sleshchenko]

It depends on eclipse-che/che#2343