pre-commit: add configuration and did some cleanup

Signed-off-by: Sumner Evans <sumner@beeper.com>

types/contentURI.go

@@ -1,28 +0,0 @@
-package types
-
-import (
-	"database/sql/driver"
-
-	"maunium.net/go/mautrix/id"
-)
-
-type ContentURI struct {
-	id.ContentURI
-}
-
-func (m *ContentURI) Scan(value interface{}) error {
-	bytes, ok := value.([]byte)
-	if !ok {
-		//return errors.New(fmt.Sprint("Failed to unmarshal value:", value))
-	}
-	if len(bytes) == 0 {
-		uri, _ := id.ParseContentURI("")
-		*m = ContentURI{uri}
-		return nil
-	}
-	return m.UnmarshalText(bytes)
-}
-
-func (m ContentURI) Value() (driver.Value, error) {
-	return m.String(), nil
-}