* detect csv delimiter in csv rendering

fixes #7868

* make linter happy

* fix failing testcase & use ints where possible

* expose markup type to template

previously all markup had the .markdown class, which is incorrect,
as it applies markdown CSS & JS logic to CSV rendering

* fix build (missing `make css`)

* ignore quoted csv content for delimiter scoring

also fix html generation

* add csv file render support defaultly

* escaping csv column content