change "goal" to "task" throughout Tour (2nd attempt)

Repeat https://github.com/HabitRPG/habitrpg-shared/pull/205 without conflicts.

In productivity contexts, "goals" tend to be large, long-term projects, whereas "tasks" are smaller actions, and I think "tasks" better matches HabitRPG's features.

"task" is used in Habit's code in many places. The wiki uses "tasks" rather than "goals" throughout, although admittedly that was a fairly recent change. Many players use "task" when describing habits/dailies/to-dos in the Tavern.
feat(rat): add rat quest
chore(i18n): use t() syntax for questEggs, grunt, update locales
Merge remote-tracking branch 'Alys/tourGoalToTask' into develop
chore(i18n): update locales, upload romanian
fix incorrect text for Light Crystals, fix Plain Egg pluralisation, remove excess word

For questEggHuntCollectPlainEgg, I've pluralised the text (Plain Eggs) because that reads better in the messages it appears in (and plurals are used in questEvilSanta2CollectTracks and questEvilSanta2CollectBranches).

For questRatCompletion, I've removed "out" from this: "we let out down our guard"
Merge pull request #211 from Alys/questFix

fix incorrect text for Light Crystals, fix Plain Egg pluralisation, remove excess word
fix typo : Canycane -> Candycane

"Candycane" had the "d" left out in headSpecialCanycaneText and headSpecialCanycaneNotes. I've inserted the "d" in all places that needed it.

I've checked all locale files and none of them had that typo.