feat(relational): implement session repository (#11109)

# Which Problems Are Solved

As part of going to a relation storage model, we need to implement the
repository for handling sessions and their events.

# How the Problems Are Solved

- Adds a migration step to create the necessary tables and types in the
database.
- Adds the repository implementation for sessions.
- Implements a projection handler for session events to handle the
events written by the old command handlers.
- Updates the `Session` type and `SessionRepository` interface:
  - added `CreatorID`
  - Adjusted `Delete` method to return amount of affected columns
  - Removed sub-repository clumns from the main interface
- Added `CreatorIDCondition`, `ExpirationCondition`, `ExistsFactor` and
`ExistsMetadata`
  - Removed `SetUserAgent`
- Methods of `SessionFactor` and `SessionChallenge` have been made
public
- fixed enumer on `SessionFactorType`
- Adds a `JSON` type to the repository package to easy can JSON columns,
resp. jsonb object inside a property of a `JSONArray` object.
- Adds a `NoChange` interface, which can be implemented to signal that a
`Change` interface implementation is not writing any changes to the
statement builder, e.g. `CTEChange`

# Additional Changes

- Fixes the operators enums. `TextOperations` had wrong comments and
`NumberOperations` additionally also had from comparisons.
- Fixes downgrade of migration step 008.

# Additional Context

- closes https://github.com/zitadel/zitadel/issues/10212

backend/v3/storage/database/repository/json.go

@@ -0,0 +1,48 @@
+package repository
+
+import (
+	"encoding/json"
+
+	"github.com/zitadel/zitadel/backend/v3/storage/database"
+)
+
+type JSON[T any] struct {
+	Value T
+}
+
+func (j *JSON[T]) Scan(src any) (err error) {
+	var rawJSON []byte
+	switch s := src.(type) {
+	case string:
+		rawJSON = []byte(s)
+	case []byte:
+		rawJSON = s
+	case nil:
+		return nil
+	default:
+		return ErrScanSource
+	}
+	if err = j.UnmarshalJSON(rawJSON); err != nil {
+		return database.NewScanError(err)
+	}
+	return nil
+}
+
+// UnmarshalJSON allows encoding/json to decode nested JSON into JSON[T] fields.
+// This makes [json.Unmarshal] work for fields inside aggregated JSON (e.g. JSON arrays).
+func (j *JSON[T]) UnmarshalJSON(data []byte) error {
+	if len(data) == 0 || string(data) == "null" {
+		return nil
+	}
+	var v T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return err
+	}
+	j.Value = v
+	return nil
+}
+
+// MarshalJSON encodes the wrapped value or null if nil.
+func (j JSON[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(j.Value)
+}