Change displayed metrics in language/component/project screens

### Describe the problem

As a community member of the Fedora community, I'd like to compare language by size.

I go to https://translate.fedoraproject.org/languages/ and see a bunch of stats.
The unit are not really written, which makes it a little bit confusing.

Here is an example: can you tell what the 35% for French is referring to without having to guess?

You may get help from this tooltip:

Thanks a lot for this great piece of software

### Describe the solution you'd like

Delete column: Unfinished characters (no idea which language may use such metrics)
For each column, explicitly write the unit or use a "ⓘ" with a tooltip to tell the unit?
For each tooltip, explicitly write the unit.

If you feel like to go further, I suggest to split the statistics in parts:
* User facing (in strings): translation progress
* Community effort (in words): translated words/untranslated words/total words
* Weblate specifics (in unit): Checks, Suggestions, comments

### Describe alternatives you've considered

_No response_

### Screenshots

_No response_

### Additional context

_No response_