Installation docs: install core library as public package
Installation docs: install core library as public package

Installing core library as a public package would allow to use it from
different tenants without the need to reimport it multiple
times. It feels like a correct addition to the docs.
Also fixes a relevant typo in the archive name.

Change-Id: Ie01b728957b1b711b5e164eeecbeca88975d5c1a

satish-avninetworks/murano,DavidPurcell/murano_temp,NeCTAR-RC/murano,olivierlemasle/murano,NeCTAR-RC/murano,NeCTAR-RC/murano,chenyujie/hybrid-murano,chenyujie/hybrid-murano,openstack/murano,olivierlemasle/murano,olivierlemasle/murano,satish-avninetworks/murano,DavidPurcell/murano_temp,DavidPurcell/murano_temp,satish-avninetworks/murano,NeCTAR-RC/murano,sajuptpm/murano,DavidPurcell/murano_temp,satish-avninetworks/murano,sajuptpm/murano,olivierlemasle/murano,openstack/murano