Add eclipse countdown API

[dgarciabriseno]

For the upcoming eclipse, we would like to create an embeddable image that gives an idea of the activity we may see during the total solar eclipse.

Tentative mockup of what the API will return:

The image will be created with the existing screenshot API with these modifications:

• Only LASCO C2 and C3 will be shown in the image
• LASCO C2 data will be brightened/saturated so it blends somewhat better with the C3 image
• An eclipse countdown printed on the top of the image
• Some text near the image dates which show what time is showing relative to the time of the eclipse.

API Parameters:

• Enable Countdown
  • This way a page may overlay their own dynamic countdown if it's embedded on a page.
• year
  • We may reuse this feature for future eclipses, so specifying the year can select which countdown to use.

The result of the API cannot be cached since the same API will always return the latest available data.

[wafels]

Add a small circle in the middle to denote the size of the moon.

[wafels]

Also, some explanatory text will have to be added - that's on me.

[dgarciabriseno]

After some work and discussion I think this API is going to be a lot simpler.
It should essentially just be a shortcut for the screenshot API with a preset FOV and using grayscale images.

Any extra text can be overlayed by whoever requests the image.