Add Portuguese voice files

[narspt]

Add Portuguese voice files.

Note: After some testing, I did normalize audio on my file at -10dB before doing AMBE encoding, I think this is a reasonable audio level comparing with the levels I listen from other DMR stations. I should say that I find the level on default English voice to be really too loud, I used to care about always turning down volume on radio every time I connect/disconnect to prevent the very loud voice sounding, unpleasant mainly at night, is it only me that find this?

[narspt]

@g4klx: sorry to ask but... is there any special reason why you are holding this PR?

[g4klx]

No reason, I just forgot!

[narspt]

No problem, thank you!