Post date using relative time

[joyously]

The date on a post is shown in relative time (3 minutes) instead of the date format chosen by the user in Settings.

[kjellr]

Related to #81. Fix will likely be the same.

[fabiankaegy]

I will take the issue 👍

[kjellr]

@fabiankaegy I think @briannaorg has this one actually, as per slack.

(Sorry for the confusion here. GitHub doesn't allow for assigning issues to people before they've issued their first commit in a repo, so it's not super-easy to "claim" these it turns out.)

[fabiankaegy]

Oops 👍

[briannaorg]

@kjellr the date shown on posts is the estimated read time, not the post date. This is a theme feature, so this issue should be closed, but issue #81 should remain open.

[kjellr]

Ah! Good catch, thanks @briannaorg. I'm going to close this one in that case. 👍

[joyously]

It should be labeled then. And the date should be shown somewhere.
Actually, if it's reading length, it should be removed, as that is plugin territory.

[briannaorg]

There's an existing twentynineteen_posted_on function to display post dates that's not being called in any template. There's no specific guideline for displaying post dates, so before I open an issue I'm going to review currently open issues and see if it's being discussed.

[designsimply]

Note: the decision to remove reading time for now was made in #139 (comment) and @briannaorg is working on an update in #168.