oAuth sample - client: propertize the oAuth server calls (host/port)

[OhadR]

oauth2.client.accessTokenUri=https://ohadr.com:8443/oauth2-auth-server/oauth/token
oauth2.client.userAuthorizationUri=https://ohadr.com:8443/oauth2-auth-server/oauth/authorize

read host ohadr.com and port 8443 as properties.