GH-1176: add NER and POS for Danish by @AmaliePauli

[alanakbik]

This PR adds support for Danish POS and NER thanks to @AmaliePauli!

Use like this:

from flair.data import Sentence
from flair.models import SequenceTagger

# example sentence
sentence = Sentence("København er en fantastisk by .")

# load Danish NER model and predict
ner_tagger = SequenceTagger.load('da-ner')
ner_tagger.predict(sentence)

# print annotations (NER)
print(sentence.to_tagged_string())

# load Danish POS model and predict
pos_tagger = SequenceTagger.load('da-pos')
pos_tagger.predict(sentence)

# print annotations (NER + POS)
print(sentence.to_tagged_string())

Closes #1176

[yosipk]

👍

[alanakbik]

👍