[Infra + Logs UI] New platform server shim

[jasonrhodes]

As part of our new platform migration , we need to implement the core shim.

See here: https://github.com/elastic/kibana/blob/master/src/core/MIGRATION.md#introduce-new-plugin-definition-shim

AC:

• Infra and logs UI server start up are both using a new platform core shim
• Implementation has been checked by the new platform team (@skaapgif probably?)

See here for more details on how this was done in APM: #34531

Notes:

Here is a list of server-side dependencies we rely on that need to be added to the shim so that we can become fully NP-compatible.

Service	Uses	Notes
server.plugins.xpack_main.registerFeature()	2
server.plugins.spaces.getSpaceId()	1

[elasticmachine]

Pinging @elastic/infra-logs-ui