Consistent and intuitive description for returned data cubes

[m-mohr]

The processes returning a data cube usually have a description such as:

A data cube with potentially lower resolution and potentially lower cardinality, but the same number of dimensions as the original data cube.

1. Check that these all are correct and complete
2. Replace "cardinality" with "number of dimension labels" (originates from Processes for climatology use cases #145 )

[m-mohr]

Things that are currently mentioned in the return value descriptions:

• cardinality (number of dimension labels)
• number of dimensions
• resolution

Is that all that changes in data cube operations?

They are mentioned like this:

filter_bands: Therefore, the cardinality is potentially lower, but the resolution and the number of dimensions are the same as for the original data cube.

How would you prefer this to be specified?

[m-mohr]

• label names?

[m-mohr]

A data cube with potentially lower resolution and potentially lower cardinality, but the same number of dimensions as the original data cube.

Replace with a list:

The data cube changes...

• resolution: <=
• number of dimension: =
• number of dimension labels: <=

Add explanation for resolution to the glossary.

[m-mohr]

That wasn't really well thought out as you'd need to do that for every dimension. Thus I kept with text and usually did something like:

A data cube with the same dimensions. The dimension properties (name, type, labels, reference system and resolution) have not changed, except for the resolution and dimension labels of the given temporal dimension.

See PR #182.