add logs to `plugin.import & export`

[samuelstroschein]

Context

Building plugins incrementally is easier if a plugin can emit warnings. Emitting warnings allows starting with a subset of a format that used by the majority of users before adding every feature of a format.

For example, i18next allows referencing other keys. Cool feature. But not supported in the inlang SDK and likely used by a tiny minority in the i18next community. Ignoring the message and emitting a warning "referencing

  "keyNesting": "reuse $t(keyDeep.inner)",

Proposal

Add an API to emit warnings.

[samuelstroschein]

After sync call with @niklas.buchfink the api is rly benefitial.

    files[0].logs = [
        level: "warning",
        bundleId: "keyContext"
        message: "This is a warning",
    ]

[samuelstroschein]

Agreed with @niklas.buchfink that warnings out of scope.

• can be added without breaking changes
• it's a nice to have