Make text module a label

[memeplex]

The text module is too inflexible: it's not possible to set left/right padding, it's not possible to change the font, etc. Why not making it a label with a %text% token by default? This would be much more flexible and also consistent with most of the other modules (consider script, for a similar one).

[memeplex]

To be more precise, what I mean is to add an implicit format = <content>. I think this will be easy to implement and mostly backwards compatible without any change of configuration (except for some format properties that will have to be moved from content to format, but the most common properties belong to both labels and formats). It's weird that the text module is almost the only one not doing this.

[memeplex]

I've pushed a PR for this. It was a bit more difficult than my previous patches but at the end I think I got it right and now I understand quite more about how polybar works so I believe I could help with another not too complex issues in the future. I would be thankful if you review the change and will try to improve anything non merge-quality ASAP.

[memeplex]

Revisiting the documentation I realized that this could be worked around, although in an admittedly hackish way, by using a format prefix or suffix which are themselves labels. Nevertheless I think having the main content as a label is not only cleaner but also more consistent with the rest of the modules.

[memeplex]

TIL about the %{T} tag (#1345) which also ameliorates the need for this refactoring. Still, the other reasons (mainly consistency) still hold.