Add Basque model v0.1.4

[zuazo]

I have made the following improvements to the previously shared model:

1. Trained from scratch with CUDA 11.6 and Tensorflow 1.15.5.
2. Added Wikipedia corpus to the scorer.
3. Optimized alpha and beta hyperparameters (134 trials).

The new accuracy:

Test Corpus	WER	CER
Common Voice	14.53%	5.28%

The models can be downloaded from here: https://aholab.ehu.eus/~xzuazo/models/Basque%20STT%20v0.1.4/

[zuazo]

Closed in favor of #27.