Implemented different ancor points for each PID elements

src/ui/panes/pid_drawing_tool.rs

src/ui/panes/pid_drawing_tool/connections.rs

src/ui/panes/pid_drawing_tool/elements.rs

src/ui/panes/pid_drawing_tool/symbols.rs

src/ui/panes/pid_drawing_tool/symbols/icons.rs

src/ui/panes/pid_drawing_tool/symbols/icons/motor_valve.rs

src/ui/panes/pid_drawing_tool/symbols/labels.rs