refactor: Extract i18n out of nav definitions

[rschristian]

Trying to get us to a point where we can load locales individually, bringing down the bundle by a few kb. Loading everything all at once isn't doing anyone any benefit.

Needs a lot of work yet

[github-actions]

Size Change: -5.97 kB (-1.33%)

Total Size: 443 kB

Filename	Size	Change
build/assets/index-********.js	27.2 kB	-5.97 kB (-18%)	👏

ℹ️ View Unchanged

Filename	Size	Change
build/assets/blog-page-********.js	258 B	+4 B (+1.57%)
build/assets/docsearch-********.js	28.9 kB	+4 B (+0.01%)
build/assets/errors-********.js	343 B	+1 B (+0.29%)
build/assets/index-********.css	9.85 kB	0 B
build/assets/repl-********.css	1.51 kB	0 B
build/assets/repl-********.js	148 kB	+2 B (0%)
build/assets/repl-page-********.js	7.66 kB	+3 B (+0.04%)
build/assets/repl.worker-********.js	213 kB	+1 B (0%)
build/assets/style-********.css	3.07 kB	0 B
build/assets/style.module-********.js	161 B	+2 B (+1.26%)
build/assets/tutorial-page-********.js	1.97 kB	-19 B (-0.95%)
build/assets/tutorial-page-********.css	1.76 kB	0 B

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