Fix Quests unit tests: allow gp and exp to be 0
i18n(notif-restyle): add strings for "menu" & "notifications"
i18n(notif-restyle): add "clear"
fix(achievements): Differentiate singular and plural

Gets rid of the clunky "(s)" on the Streak and Perfect Day achievements, and makes a few other textual improvements.
chore(i18n) add notice about translations
chore(i18n:): implement i18n module, start moving content to locales/en/content.json, recompile
improve(i18n): add locales for content.json, add code for server to i18n, build
chore(i18n): remove content.json locales for now
chore(i18n): move all the weapons to content.json and update README.md
chore(i18n): move armor items to content.json
chore(i18n): start moving attributes values to interpolation
chore(i18n): move attributes values to interpolation
chore(i18n): move head items to strings
improve(i18n): move gear strings to gear.json, recompile
improve(i18n): move potion to strings, add content.json for generic content
fix(i18n): remove duplicate strings
fix(i18n): remove duplicate strings
improve(i18n): move spells to strings
fix(i18n): json syntax
improve(i18n): move eggs to strings