Sell trash you can find in bushes

[paris-ci]

It would be nice to be able to sell everything we can find in bushes for a few exp bonus

• [ ] Add setting : min_exp_sell_trash (int, default=0)
• [ ] Add setting : max_exp_sell_trash (int, default=3)
• [ ] Add column : exp redeemable (int) (@Diagamma)
• [ ] Add a new subcommand to shop : !shop sell to redeem exp

[paris-ci]

Idea by @『Deus Ex Maskass』#9681