Use ro.boot.serialconsole to disable console services

For many years, services declaring "console" would only be started if the
console device specified by androidboot.console= was present under /dev.
However, they would also be started if the /dev/console node existed.

This fallback causes problems with newer GKI kernel images which now
hard-code "console=ttynull" via CONFIG_CMDLINE, which essentially means
/dev/console always exists, even though this console points nowhere.

It also causes problems on devices where the androidboot.console was not
the same as the kernel dmesg console ("console="), such as cuttlefish,
because those platforms could not simultaneously enable kernel logging
but disable the interactive serial console feature. The framework just
assumed both would be muxed on the same serial port. Cuttlefish had a
workaround, to use "androidboot.console=invalid" to avoid the fallback,
but this doesn't work on devices which still want to mux the kernel logs
and interactive serial console.

This change resolves the issue in a better way, by introducing a new
boolean property called "androidboot.serialconsole". Setting this to "0"
will disable the console services, regardless of whether the
/dev/console or /dev/${ro.boot.console} devices exist. Older kernels
and bootloaders don't need to set this and can rely on the old behavior
in init, but bootloaders booting newer kernels must set it to avoid the
"performance is impacted" message due to console services being started.

Bug: 266982931
Bug: 223797063
Bug: 267428635
Test: "launch_cvd" with "androidboot.console=invalid" removed;
      See the "performance is impacted" message.
Test: "launch_cvd" with "androidboot.serialconsole=0";
      The "performance is impacted" message is gone.
Change-Id: Iaad4d27ffe4df74ed49606d3cabe83483c350df4