The stable charts repository is nearing the end of its life. Once
that has happened those who attempt to run helm init will get an
error. This flag provides a means to still use Helm v2 after the
stable charts repository is gone.
A secondary situation is that Helm v2 can be used in environmnets
without a network connection.
Closes#7868
Signed-off-by: Matt Farina <matt@mattfarina.com>