Allow customizing annotations

[Alphare]

Both the gutter and the inline annotations currently have a format that might not be optimal for everyone.

I would personally leave the inline as they are, but I would love to shorten the gutter to just the short author and short hash, equivalent to hg annotate -cu FILE.

I have a vertical monitor for my IDE and the current gutter annotations basically take up half of my screen to show a truncated commit title and the date.

I think "simply" allowing the user to define the right subset of annotate flags in the settings would work fine, what do you think?