Change trackfinder labels

Currently `EMTF` is labeled as `FWD` in the testbench and in the LUT content files. This should be changed to sync with the changes in dinyar/uGMTfirmware#225. To streamline the naming the following convention should be used:
- `FWD` -> `EMTF`
- `BRL`/`BAR` -> `BMTF`
- `OVL` -> `OMTF`
- `FTRK` -> `ETRK`
- `FIMD` -> `EIMD`
