Update authorisation to user bearer tokens

[forgetso]

Update get traffic API calls to use bearer tokens. See prosopo/captcha#2294 for details.

[light-source]

Auth switch PRs for the getSiteWpDetails API endpoint:

1. AWS-related PR
2. (WordPress repo PR)

It works locally, but AWS PR fails tests, on the job-runner package, which I didn't touch, so it seems unrelated to this PR.

In addition, I noticed @keyring use-related issues, which prevents the package build for the client-side.

It means in order to release the new WordPress plugin version:

1. AWS-related PR must be merged & released
2. @keyring-related issues must be fixed