[docs] Move all the futurey bits of LibraryEvolution.rst to a new file (#28007)
[docs] Move all the futurey bits of LibraryEvolution.rst to a new file (#28007)

It's not /exactly/ a manifesto but it's close enough.
hooman/swift,tkremenek/swift,stephentyrone/swift,jckarter/swift,parkera/swift,tkremenek/swift,xwu/swift,hooman/swift,ahoppen/swift,allevato/swift,gregomni/swift,harlanhaskins/swift,karwa/swift,ahoppen/swift,airspeedswift/swift,xwu/swift,nathawes/swift,tkremenek/swift,airspeedswift/swift,glessard/swift,apple/swift,allevato/swift,gregomni/swift,airspeedswift/swift,roambotics/swift,CodaFi/swift,airspeedswift/swift,hooman/swift,xwu/swift,benlangmuir/swift,ahoppen/swift,tkremenek/swift,stephentyrone/swift,gribozavr/swift,rudkx/swift,karwa/swift,stephentyrone/swift,atrick/swift,gribozavr/swift,gregomni/swift,rudkx/swift,gribozavr/swift,nathawes/swift,gregomni/swift,parkera/swift,JGiola/swift,CodaFi/swift,glessard/swift,harlanhaskins/swift,harlanhaskins/swift,jckarter/swift,aschwaighofer/swift,gribozavr/swift,harlanhaskins/swift,aschwaighofer/swift,stephentyrone/swift,glessard/swift,jmgc/swift,rudkx/swift,benlangmuir/swift,apple/swift,lorentey/swift,jckarter/swift,jckarter/swift,airspeedswift/swift,lorentey/swift,allevato/swift,apple/swift,CodaFi/swift,benlangmuir/swift,benlangmuir/swift,karwa/swift,glessard/swift,CodaFi/swift,gregomni/swift,lorentey/swift,tkremenek/swift,atrick/swift,allevato/swift,xwu/swift,jmgc/swift,jmgc/swift,lorentey/swift,ahoppen/swift,tkremenek/swift,parkera/swift,rudkx/swift,airspeedswift/swift,atrick/swift,JGiola/swift,glessard/swift,stephentyrone/swift,hooman/swift,nathawes/swift,airspeedswift/swift,lorentey/swift,stephentyrone/swift,JGiola/swift,karwa/swift,aschwaighofer/swift,harlanhaskins/swift,rudkx/swift,nathawes/swift,aschwaighofer/swift,karwa/swift,jmgc/swift,apple/swift,JGiola/swift,atrick/swift,gregomni/swift,benlangmuir/swift,stephentyrone/swift,rudkx/swift,JGiola/swift,allevato/swift,roambotics/swift,roambotics/swift,jckarter/swift,allevato/swift,ahoppen/swift,xwu/swift,parkera/swift,JGiola/swift,harlanhaskins/swift,gribozavr/swift,xwu/swift,CodaFi/swift,parkera/swift,aschwaighofer/swift,lorentey/swift,roambotics/swift,karwa/swift,glessard/swift,benlangmuir/swift,gribozavr/swift,harlanhaskins/swift,gribozavr/swift,jckarter/swift,ahoppen/swift,nathawes/swift,jmgc/swift,jckarter/swift,allevato/swift,lorentey/swift,CodaFi/swift,parkera/swift,roambotics/swift,CodaFi/swift,atrick/swift,nathawes/swift,apple/swift,lorentey/swift,jmgc/swift,jmgc/swift,tkremenek/swift,atrick/swift,xwu/swift,aschwaighofer/swift,karwa/swift,hooman/swift,parkera/swift,roambotics/swift,hooman/swift,parkera/swift,karwa/swift,hooman/swift,gribozavr/swift,apple/swift,nathawes/swift,aschwaighofer/swift