Teeracle: `SendWithCertificateVerification` behaviour should be more roboust

[OverOrion]

Coingecko changed their certificate (authority) for their API endpoint from Let's encrypt #1162 and now it seems they changed it back, resulting in fetching failure.

Our current solution relies on that we pass a single root_cert not a collection of trusted root certificates, which in cases like this causes problems, because for a fix to be applied a rebuld / redeployment is needed.
I can see why it was implemented like this, but because this is a 3rd party we should not rely on the fact they will never change their certificate (authority).

Proposed solutions:

1. Use the default trusted store of the http_req library, mimicking what a browser would do
2. Add the option to specify a custom trusted store for SendWithCertificateVerification so it could handle a collection of certificates, instead of just one.

[OverOrion]

Currently the CI fails because of coingecko changing their certificate once again:
https://github.com/integritee-network/worker/actions/runs/5155951839/jobs/9319706548

A hotfix has been submitted, but a long-term solution will be implemented as well.