update to use sqlalchemy

- change from mysql-connector-python to sqlalchemy
    - allow for connection to sqlite3, mysql, mariadb, postgres, and
oracle databases
- change `DATE` columns to `DATETIME` type
- add WHO columns
- install database connectors and required packages

env.example

@@ -1,12 +1,11 @@
 LISTEN_ADDRESS=0.0.0.0 # Lisen on all interfaces
 LISTEN_PORT=8080 # Internal port number
 MPV_SOCKET=/tmp/mpvsocket # Path to mpv socket
-
-# MySQL connection info
-MYSQL_HOST=localhost
-MYSQL_USER=mpvuser
-MYSQL_PASSWORD=SecretPassword
-MYSQL_DATABASE=mpv
-MYSQL_PORT=3306
-
 LOGLEVEL=info
+
+# Options:
+# mysql+pymysql://<user>:<password>@<host>[:<port>]/<dbname> - works with MySQL and Mariadb
+# postgresql+psycopg2://user:password@host:port/dbname[?key=value&key=value...]
+# sqlite:///path
+# oracle+oracledb://user:pass@hostname:port[/dbname][?service_name=<service>[&key=value&key=value...]]
+DATABASE_URL=mysql+pymysql://user:password@localhost:3306/mpv