it says that the total current of all VDD power lines (source) is maximum of 105mA
Actually that's not what this table is about.
Table 23 is in the section "6.2 Absolute maximum ratings" of the datasheet. These ratings are the voltages and currents which should never be exceeded. If you do so anyway you risk damaging the chip.
The current consumption of a chip like a microcontroller mainly depends on:
how fast you run it (clockspeed)
how much it is doing (more active means more current, power down/standby means less current).
how much current it needs to power other parts of the circuit
An example of that last point: if a GPIO pin needs to light up an LED directly, it might need to supply (source !) 5 mA. That 5mA needs to come through a VDD pin so it is part of that 105 mA max current. So power 21 LEDs at 5 mA and you're at that maximum. If you would use a MOSFET to switch on/off the LED then the GPIO pin only needs to charge/discharge the gate of that NMOS, that costs almost no supply current for the microcontroller.