In html, tags are case-insensitive. However, owl templates aren't,
as nodes starting with a capital letter are considered as component
nodes (not html). This means that people can use capital letters in
form or kanban archs for html nodes and it should work.
Before this commit, it didn't, because the compiler kept the case
when generating the owl templates. For instance, an arch like
`<form><Div/></form/>` produced the error 'Cannot find the
definition of component "Div"'. This commit fixes the issue.
Part-of: odoo/odoo#108221
Aaron Bohy
7095310672