Missing config schema

Problem/Motivation

The BigInt module has not defined any config schema. This becomes especially apparent when you attempt to enable BigInt in a Kernel test, where it's a dependency of a module you're trying to test. If you attempt to create a bigint field in the Kernel test you get the following error:

Drupal\Core\Config\Schema\SchemaIncompleteException: Schema errors for field.storage.media.field_pinned_ids with the following errors: field.storage.media.field_pinned_ids:settings.unsigned missing schema, field.storage.media.field_pinned_ids:settings.size missing schema

Proposed resolution

Provide a config schema defining the field storage and field settings.

Remaining tasks

Create a patch.

User interface changes

None.

API changes

None.

Data model changes

The config created when you define a bigint field will be properly typed! Horay!

Release notes snippet

Defines the schema for the config provided by this module.