Replace size tag with scale

[bruvellu]

Describe what's not optimal
Size is a generic name that can be mistaken for file size (MB) or image resolution (2000px).

Describe what could be done to improve (optional)
Change all instances of size for scale.

[bruvellu]

I started creating a Scale model, but that felt like an overkill for this feature. For now, I'll make scale be a field of Media with the choices described in this comment.

That means, I'll remove the Size tag category and its descriptions. Here they are for the record:

<0,1 mm / <0.1 mm / micro / Organismos unicelulares e detalhes de organismos multicelulares. / Unicellular organisms and details of multicellular organisms.
0,1 - 1,0 mm / 0.1 - 1.0 mm / tiny / Embriões, larvas e seres planctônicos. / Embryos, larvae and planktonic creatures.
1,0 - 10 mm / 1.0 - 10 mm / visible / Seres diminutos, mas visíveis a olho nu. / Tiny creatures but visible at the naked eye.
10 - 100 mm / 10 - 100 mm / large / Organismos macroscópicos. / Macroscopic organisms.
>100 mm / >100 mm / huge / Organismos ainda maiores. / Even larger organisms.

[bruvellu]

Applied changes in 4f14e91. The former Media.size is now Media.scale. It's a choice field with five options:

SIZE_CHOICES = (
    ('micro', _('<0,1 mm')),
    ('tiny', _('0,1–1,0 mm')),
    ('visible', _('1,0–10 mm')),
    ('large', _('10–100 mm')),
    ('huge', _('>100 mm'))
)

A few things are pending:

• Removing the size category and its size tags. I think it makes sense to keep the scale as a field apart, and not a tag anymore. The main reason is that it gets complicated to get the media size, having to filter tags by category.
• Including the scale field in the main search form.
• Including the scale field in the dashboard metadata editing forms. ded00f3

And a question remains. Should the scale be a model with its fields? To be decided later…

[bruvellu]

After removing the size tags, the size descriptions in the organization page broke. Having a Scale model is indeed the best option. But since it involves additional modifications in the metadata forms, for example, this will have to be postponed for now.