base: user 'Login' and 'Register' button  addition

(addresses #1943)

Signed-off-by: Eirini Psallida <eirini.psallida@cern.ch>
I think this is not doing what you want as it's evaluated as 

``(config.CFG_ACCESS_CONTROL_LEVEL_ACCOUNTS == 0) or 1``

``(config.CFG_ACCESS_CONTROL_LEVEL_ACCOUNTS == 0) or (config.CFG_ACCESS_CONTROL_LEVEL_ACCOUNTS == 1)``

or 

``config.CFG_ACCESS_CONTROL_LEVEL_ACCOUNTS in [0, 1]``