Support CA in the LB code

[scylladb-buff]

Currently, the alternator LB code example does not allow you to specify the certificate authority root certificate. In a recent cloud release, all cluster certificates are signed by a service-wide CA that can be downloaded from the cloud and API. We need to add support for this.

There is a workaround adding the root certificate to the OS chain of trust, but in some user setups, this might not be the best solution. The change is related to: alternator-load-balancing/go/v2/alternator_lb.go at 3b898423cb9246e2b2a63300762b499ce46db8b0 · scylladb/alternator-load-balancing

[scylladb-buff]

@dkropachev is this something that you can do as part of the drivers project?

CC: @nyh

[dkropachev]

@scylladb-buff , is there any urgency behind this ? I can't push it to this sprint or next sprint unless it is urgent.

[dkropachev]

@scylladb-buff, @mykaul, this repo is not under scylla-driver umbrella and therefore I don't have access, could you please take a look at this PR

[ksinica]

@scylladb-buff, @mykaul, this repo is not under scylla-driver umbrella and therefore I don't have access, could you please take a look at this PR

Shouldn't this be supported in all language flavors, not only Go? Pardon if you're planning to add this feature in a separate pull request; just wanted to be sure of that.

[scylladb-buff]

We should add this to all drivers, but the priority for the rest is lower.