Add delay before starting camera

[MarSoft]

On the ESP32Cam board, when you try to start the camera right after boot-up,
it will give an error, like this:
[E][sccb.c:115] SCCB_Write(): SCCB_Write Failed addr:0x30, reg:0xc7, data:0x10, ret:-1
And then it will fail to init.
They say it is related to poor power supply.

But after I added this 500ms delay, the issue gone.
I suppose it's because after the board boot-up, there is a bunch of things initializing
and comsuming power, which causes camera voltage to be unstable.
And if we wait a bit then those initializations are over
and voltage is more stable.

[DjSteker]

very good solution, I like it because it also takes care of the other components