[ipcamera] Fix several issues and some improvements (#11300)

[ipcamera] Fix several issues and some improvements (#11300)

* Fixes an issue now that the binding is not polling the snapshot anymore where the jpg could return an old image from cache.
* Fixes an issue that could be caused if you spammed the refresh key whilst watching ipcamera.mjpeg
* Improvements in stopping the servlet and stopping any open streams if the pause button is pressed on a camera thing.
* Reduces memory, thread and open file descriptor resource use.
* Fixes empty passwords create bad log output for logged ffmpeg commands.
* Fix for INSTAR cameras that created a WARN about bad user/pass when setting up the alarm server.

Closes #11301

Signed-off-by: Matthew Skinner <matt@pcmus.com>