Revert "Revert "FormulaInstaller: make mode reader methods private""
Revert "Revert "FormulaInstaller: make mode reader methods private""

This reverts commit c622f27e525de4a9cc9a209a6cc0e26be60b5919.

ilovezfs/brew,hanxue/linuxbrew,nandub/brew,ilovezfs/brew,JCount/brew,zmwangx/brew,MikeMcQuaid/brew,mgrimes/brew,muellermartin/dist,nandub/brew,staticfloat/brew,staticfloat/brew,EricFromCanada/brew,reitermarkus/brew,aw1621107/brew,bfontaine/brew,amar-laksh/brew_sudo,mistydemeo/homebrew,EricFromCanada/brew,tonyg/homebrew,mistydemeo/homebrew,staticfloat/brew,alyssais/brew,hanxue/linuxbrew,reitermarkus/brew,rwhogg/brew,DomT4/brew,MikeMcQuaid/brew,bfontaine/brew,pseudocody/brew,nandub/brew,JCount/brew,Linuxbrew/brew,EricFromCanada/brew,DomT4/brew,reelsense/brew,JCount/brew,aw1621107/brew,claui/brew,toonetown/homebrew,vitorgalvao/brew,tonyg/homebrew,gregory-nisbet/brew,toonetown/homebrew,Linuxbrew/brew,toonetown/homebrew,konqui/brew,palxex/brew,mgrimes/brew,Linuxbrew/brew,mistydemeo/homebrew,vitorgalvao/brew,gregory-nisbet/brew,konqui/brew,jmsundar/brew,reitermarkus/brew,ilovezfs/brew,gregory-nisbet/brew,palxex/brew,Homebrew/brew,AnastasiaSulyagina/brew,DomT4/brew,rwhogg/brew,nandub/brew,Homebrew/brew,vitorgalvao/brew,vitorgalvao/brew,alyssais/brew,mahori/brew,EricFromCanada/brew,hanxue/linuxbrew,claui/brew,mgrimes/brew,zmwangx/brew,Homebrew/brew,MikeMcQuaid/brew,sjackman/homebrew,amar-laksh/brew_sudo,claui/brew,sjackman/homebrew,claui/brew,sjackman/homebrew,mahori/brew,pseudocody/brew,muellermartin/dist,pseudocody/brew,mahori/brew,MikeMcQuaid/brew,sjackman/homebrew,zmwangx/brew,jmsundar/brew,bfontaine/brew,konqui/brew,muellermartin/dist,jmsundar/brew,palxex/brew,AnastasiaSulyagina/brew,AnastasiaSulyagina/brew,maxim-belkin/brew,maxim-belkin/brew,konqui/brew,alyssais/brew,gordonmcshane/homebrew,aw1621107/brew,reelsense/brew,Homebrew/brew,amar-laksh/brew_sudo,gordonmcshane/homebrew,maxim-belkin/brew,DomT4/brew,tonyg/homebrew,gordonmcshane/homebrew,JCount/brew,reitermarkus/brew,reelsense/brew,mahori/brew,rwhogg/brew,Linuxbrew/brew