Secretless component quality levels move from alpha/beta/GA to community/trusted/certified

[izgeri]

We defined certification levels (CLs) after Secretless had its 1.0 release, but we haven't moved Secretless from qualifying providers / connectors / config managers as alpha/beta/stable to using the new certification level community/trusted/certified nomenclature.

In this issue, we will update the Secretless README / internals to be clear about the certification levels of the internal components.

AC:

• List all internal components with their certification levels in the README
• Ensure all Community components have a README in their implementation folder that includes basic details about how to use the component
• Ensure the README links to READMEs and/or doc pages for all components
• Ensure the README is clear about the CLs of each component
• If any docs pages need to be updated (for example, to say Trusted instead of Beta), a corresponding docs issue is filed and linked in this PR
• (Optional) if any components are close to being a higher CL, file issues to do the work required to promote the CL of the component (e.g. for the generic HTTP connector)