PocketBase: v0.4.0 Release

## Changes - Added support for import/export of collections configuration. > :warning: This feature is still experimental, so use it cautiously and always have a backup of your `pb_data` before applying the import! - Added new API endpoint to bulk import collections. - Updated the JavaScript and Dart SDKs accordingly with the new endpoint `client.collections.import(...)`. - Added new Import/Export section in the _Admin UI > Settings_. When importing you'll be able to "Review" your changes with a side-by-side diff before sending them to the server. Validations on the imported collections, eg. missing required fields, are done **only server side** after submitting the import form. The import is executed within a transaction and it is applied only after all imported collections changes are applied successfully. - Added migration command to export the local collections configuration into a migration file ```sh go run main.go migrate collections ``` > **NB!** This will works only for new project - more info on the caveats you could find in the [DB Migrations guide](https://pocketbase.io/docs/db-migrations/#collections-migration). - All resource endpoints (records, collections, admins, users, etc.) now support specifying an optional custom insertion id during create (**it must be a fixed 15 chars string**) to allow handling offline first data structures [#246]. - The realtime **create** and **update** hooks are now fired when updating a record manually with the `Dao` - All examples are updated to use `127.0.0.1` instead of `localhost` because the `localhost` hostname may not be available on some Windows installations and on some platforms could resolve differently (Node17+ for example has higher priority for the ipv6 version [::1], which could lead to connection failure - [pocketbase/js-sdk#21](https://github.com/pocketbase/js-sdk/issues/21)). - Added **totalPages** field in the api response (the SDKs were also updated to reflect the change in the result object dto). - Added the build version number in the Admin UI footer (#280). - Updated the _Thumbs_ file option tooltip to include info about the default/system `100x100` thumb (thanks @ollema). - _Internals_: - Added `OnCollectionsBeforeImportRequest` and `OnCollectionsAfterImportRequest` hooks. - Updated the `base.Model` interface with additional `MarkAsNew` and `UnmarkAsNew` for finer control over the upsert operations on existing models. - Added `form.*WithConfig(...)` factory to all `forms` models to allow nesting and running multiple forms within a single DB transaction - The `OnModelAfter*` hooks for transactions are now fired **only after a successful transaction commit** (in the order they were initially called during the transaction). - Other minor code and tests improvements.