RTSPCameraAgent: connection robustness

[davidvng]

Description

• Move connection to camera stream to its own function
• Continue loop instead of stopping acq process when snapshot fails
• Add connected to session.data and OCS feed

Motivation and Context

Resolves #809

How Has This Been Tested?

Tested on daq-dev

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[BrianJKoopman]

Thanks for this! There's one bug with the connected status, but otherwise looks good.

[BrianJKoopman]

Looks good, thanks for the changes!