Set html lang and alternate lang urls

[tusbar]

This will prevent duplicate SE entries for different languages.

[buildsize]

File name	Previous Size	New Size	Change
page-_error.js.gz	171 bytes	172 bytes	1 bytes (1%)
page-catalog.js.gz	57.61 KB	57.6 KB	-4 bytes (0%)
page-catalogs.js.gz	3.71 KB	3.71 KB	0 bytes (0%)
page-dataset.js.gz	18.45 KB	18.45 KB	-1 bytes (0%)
page-doc-publish-your-data.js.gz	3.75 KB	3.75 KB	0 bytes (0%)
page-doc.js.gz	1.92 KB	1.92 KB	0 bytes (0%)
page-events.js.gz	1.62 KB	1.62 KB	0 bytes (0%)
page-harvest.js.gz	3.14 KB	3.14 KB	0 bytes (0%)
page-index.js.gz	6.17 KB	6.17 KB	0 bytes (0%)
page-legal.js.gz	853 bytes	853 bytes	0 bytes (0%)
page-publication-datasets.js.gz	6.08 KB	6.08 KB	0 bytes (0%)
page-publication-organization.js.gz	9.65 KB	9.65 KB	0 bytes (0%)
page-publication-producers.js.gz	5.61 KB	5.61 KB	1 bytes (0%)
page-publication.js.gz	3.81 KB	3.81 KB	0 bytes (0%)
page-search.js.gz	7.99 KB	7.99 KB	1 bytes (0%)
page-doc-link-proxy.js.gz	1.49 KB	1.49 KB	0 bytes (0%)
page-embed-preview.js.gz	4.62 KB	4.62 KB	0 bytes (0%)
chunk-dataset_downloads_preview_table.js.gz	12.9 KB	12.9 KB	0 bytes (0%)
page-_app.js.gz	2.51 KB	2.78 KB	281 bytes (11%)
static-commons-main-[hash].js.gz	134.88 KB	134.96 KB	81 bytes (0%)
chunk-centered_map_map.js.gz	169.97 KB	169.97 KB	0 bytes (0%)

[codecov-io]

Codecov Report

Merging #634 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master    #634      +/-   ##
=========================================
- Coverage    4.94%   4.93%   -0.01%     
=========================================
  Files         111     111              
  Lines        1477    1478       +1     
=========================================
  Hits           73      73              
- Misses       1404    1405       +1

Impacted Files	Coverage Δ
server/index.js	0% <ø> (ø)	⬆️
lib/i18n.js	0% <0%> (ø)	⬆️

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