Allow POST requests on /compile for non-url contents

[heytdep]

Currently, there is no way to pass the data of the text parameter in /compile with a POST request (https://latexonline.cc/compile?text={latexCode}).

This makes compiling long documents through this endpoint and without using a URL (which is not optimal when you only have user-entered input and don't want to upload it to github first for both security and optimization purposes) impossible since a 414 error (request-uri too large) is returned when trying to compile a long tex code.

Allowing also POST requests should fix this issue.

[kpym]

You can POST .tar archive to https://texlive2020.latexonline.cc/data. You can check this in latexonline bash script.