Closes: #40067

Read all bridges from the dummy file, not only the first one. And use
dummy bridges only for requests without valid shim-token.

opendkim produces 'Authentication-Results' header to indicate if the
dkim signature is valid, but nothing in our current infraestructure
produces or reads X-DKIM-Authentication-Results. Check only for
'Authentication-Results' so an attacker will not be able to fake an
email without really comming from an authorized provider.

Closes #40058

Closes #40057

Use lektor-scss to build the SCSS during the lektor site build

See merge request !46

Fix <picture> not rendering on prod

Closes #40055

See merge request !45

Fixes broken CSS on the production site

Closes #40055

Context: https://gitlab.torproject.org/tpo/tpa/team/-/wikis/policy/tpa-rfc-30-change-lego-plugins

CI recently began failing with our bundled version of environs. The fix
is to Implement TPA RFC 30, and manually install environs

After the rewrite, many tests are broken and have either been fixed or disabled

Check if the shim-token header is present and valid on moat requests, to
make sure the request is comming from the shim. If not respond with
dummy bridges comming from a configured file.