This change fixes some minor errors in the blubber image build:
move used directory from /srv/org/wikimedia/static-tendril to /srv/app/html/statictendril
remove redirect to 443
remove custom and errorlog, use /dev/stderr
rename html file form static-tendril-index.html to index.html
rename blubber variant from bienvenida to statictendril

Bug: T340182