fix(templates): Remove hardcoded language from document template

Remove hardcoded en-US language attributes (fo:language, fo:country,
style:language-asian, style:country-asian, style:language-complex,
style:country-complex) from the default styles in document.ott so that
new documents inherit the user's locale instead of forcing English (USA).

Fixes #496

Signed-off-by: Julius Knorr <jus@bitgrid.net>

Author: juliusknorr