Add support for conversion to-/from Degrees Minutes Seconds (D° M' S"), Decimal Minutes (D° M.M'), and Decimal Degrees (D.D°)

Many systems on boats store GPS positions using formats not suitable for computers. My experience is that the decimal degrees works best for computers and moving data between systems. I asked on [Discord](https://discordapp.com/channels/909674491309850675/1176493400095211642/1216648542114812034) and were suggested to create this issue here :-) So here it goes:

If the spatial extension could add support for reading the following formats convert to decimal degrees (numerical) it would be very helpful.

Priority would be to read from

* Degrees Minutes Seconds (D° M' S") `45° 46' 52" N 108° 30' 14" W`

* Decimal Minutes (D° M.M') `45° 46.8666' N 108° 30.2333' W`

and convert to Decimal Degrees (D.D°) -> `45.7811111° N 108.5038888° W`

So the end result should be `45.7811111 -108.5038888 ` assuming a positive value for North and East, a negative value for South and West.