Update adaptor icons and schemas list for new adaptors

When we release a new adaptor, we have to restart lightning for it to show in the icons picklist

But even then we're not done - we have to do something magical to get the icon to appear on the diagram. I think it even takes a release? Otherwise we just see this:

The ultimate aim of this and #2209 is to make it so that whenever an adaptor (new or existing) is released to npm, the sales and services teams can start using it with as little effort as possible

We currently fetch the adaptor icons and schemas independently, leaving us with three ways adaptors are realised within the application (the third being the AdaptorRegistry, see: #2209)

We shouldn't be bound to a single build step in order to have the information we need to serve adaptor icons or schemas.

We prefer hosting adaptor icons locally but in the case of a new adaptors icon not being in the containers filesystem, we should see if we can redirect the request to jsdeliver - or better yet have the adaptor registry keep a url in memory to either the Lightning backend or to jsdeliver.