HTTPCameraAgent Handle token lease and usage

[davidvng]

Description

Add logic to handle Reolink's API token. Grabs token if doesn't already have one or lease is close to expired.

Motivation and Context

The agent grabbed a token in each loop before, reaching the limit of 20 max tokens per account.

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]

Looks good to me, just one suggestion about input of the --renew-token duration. See below.