0.8.0 Release Candidate 3

Changes:

• Quite possibly fixing ingress for addon users (or at least until the next bug is found)
• Fix initial state of mqtt switches
• Gracefully handle edge case when frame is no longer in cache

Images:

• x86: blakeblackshear/frigate:0.8.0-rc3-amd64
• x86 w/ nvidia (for ffmpeg only): blakeblackshear/frigate:0.8.0-rc3-amd64nvidia
• Raspberry Pi 3/4 (32bit): blakeblackshear/frigate:0.8.0-rc3-armv7
• Raspberry Pi 4 (64bit): blakeblackshear/frigate:0.8.0-rc3-aarch64