Social Links Block: Allow plugins to change the default links inserted

[jasmussen]

In #16897 a "social links" block is likely to land in its first version.

Based on feedback for that first version, we'd like to explore some additional features.

When you insert a social links block, 6 links will be inserted by default:

It would be nice to surface a simple way for plugins or themes to change what those default links are, to better tailor the experience.

[paaljoachim]

Is this issue still valid?

[jasmussen]

Excellent point! No it isn't! Because no links are inserted anymore. Thank you Paal.