Set bigger client_max_body_size for Nginx

[Samuel Jimenez]

MeilISearch max payload is being changed by default to 100M in meilisearch/meilisearch#1147. This should be reflected by the nginx .conf by adding

client_max_body_size 100M;

at http in

/etc/nginx/nginx.conf

This modification should be documented somewhere :)

[Clémentine]

Should be done once the next release of MeiliSearch is out 😊