Edit README to introduce API Keys and explain the difference, as the …

[streamnsight]

Description

Edit README to introduce API Keys and explain the difference, as the 2 are different ways of authenticated and API keys users should not use this package.

Type of change

Please delete options that are not relevant.

• 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)
• This change requires a documentation update

How Has This Been Tested?

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[streamnsight]

@upfixer @ahosler

[streamnsight]

Note: API Keys docs points to this package, so it can be very confusing.