declarative config: ability to skip server certificate verification

[SylvainJuge]

As discovered in #1054, there is no way to call setSslContext with declarative config, so we should ideally contribute this upstream.

• try to contribute the feature upstream: both in configuration and in implementations
• if not possible as a direct upstream implementation, we need to evaluate using transparent workarounds for the end-users (adding an edot option is fine, modifying the exporter config is not).