two different keys set the same key in .env for the leading `AIO_` prefix (quirk)

[shazron]

For an .env file

AIO_RUNTIME_AUTH=foo
AIO__RUNTIME_AUTH=bar

Both keys are effectively the same key runtime.auth
This will not be apparent to the user, and may just be a documentation issue.

AIO_RUNTIME_AUTH is processed as runtime.auth
AIO__RUNTIME_AUTH is processed as .runtime.auth (note the leading period). The leading period is split out when calling setValue.

Fix:

Document that any .env vars that are prefixed by AIO_ or AIO__ are equivalent (one or two underscores). Anything more than two will be reflected as an underscore itself.

[purplecabbage]

Yeah, _ is interpreted as . and (double) __ become _
However, this is applied after AIO_ so it looks like we discard the leading .

AIO_CASE=1 => case:1
AIO_CASE_TWO=2 => case: { two: 2 }
AIO_CASE__THREE=3 => case_three:3

[aiojbot]

JIRA issue created: https://jira.corp.adobe.com/browse/ACNA-2229