Task/DB-Migration: Add Key-Value to SQL Migration functionality. (#3380)

* feat(go): add db package;

* feat(go): add jobs table;

* feat(go): add schema migration facade;

* refactor(go): use custom key type to avoid collisions;

db/sqlite.go

@@ -0,0 +1,54 @@
+package db
+
+import (
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+	"os"
+	"path/filepath"
+)
+
+// sqliteConnector for initializing and
+// connecting to a sqlite database.
+type sqliteConnector struct{}
+
+// sqliteConnector.connect connects and
+// initializes a connection to sqlite.
+func (s *sqliteConnector) connect() (*gorm.DB, error) {
+	// ensure data dir exists.
+	_, err := os.Stat("data")
+	if err != nil {
+		if os.IsNotExist(err) {
+			err = os.Mkdir("data", 0700)
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			return nil, err
+		}
+	}
+
+	dbFilePath := filepath.Join("data", "netmaker_v1.db")
+
+	// ensure netmaker_v1.db exists.
+	_, err = os.Stat(dbFilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			file, err := os.Create(dbFilePath)
+			if err != nil {
+				return nil, err
+			}
+
+			err = file.Close()
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			return nil, err
+		}
+	}
+
+	return gorm.Open(sqlite.Open(dbFilePath), &gorm.Config{
+		Logger: logger.Default.LogMode(logger.Silent),
+	})
+}