Reccomendation: Update labels.

[mankoff]

GitHub allows bulk-labeling. I've just searched existing issues for certain words (e.g. wdir) and then bulk-added the WindDirection tag to all of those issues. I did the same for some years. I did not do other instruments.

This database is growing large enough that metadata is becoming more important. That means labels. The number of possible issue types, sensors, locations, and times is also growing larger. I therefore recommend updating and simplifying the labels. Fewer labels should, hopefully, increase label usage. It would also make the homepage Readme easier to maintain.

We could limit times to 5-year bins rather than annual resolution.

We should probably group stations. Rather than having NUK_L and NUK_U, just have one NUK label.

If the above changes are implemented, we've reduced the information contained in the tag, so the content needs to include this (e.g., make it clear to someone which NUK station and which year is the issue based on the text body).