EZP-23742: Add PlatformUI bundles to ezpublish-community composer.json

JIRA: https://jira.ez.no/browse/EZP-23742 (sub-task of https://jira.ez.no/browse/EZP-23128 and thus requires https://github.com/ezsystems/PlatformUIBundle/pull/136)

# Description

Adds the PlatformUIBundle dependency to ezpublish-community. It also changes the default REST Auth method to session (until [maybe we can support both](https://jira.ez.no/browse/EZP-22192))

# Tests

manual tests
This shouldn't be needed. `ezsystems/platform-ui-assets-bundle` should be a dependency of `platform-ui-bundle`.
Furthermore, `0.1` is far too restrictive. I'd say `~0.1`