Fix local storage usage
Fix local storage usage

JS local storage saves all values as strings.
Access token expiration and issue dates were handled wrong in cases like
issueDate + expiresIn were concatenated as strings.

Change-Id: Ic15a320f056e317fe7cf0da66622df664ba7ed35

ColdrickSotK/storyboard-webclient,ColdrickSotK/storyboard-webclient,ColdrickSotK/storyboard-webclient