Add more Recurring Events on community page

[pitag-ha]

I was just having a look a the community page and was noticing that a few events might be missing. E.g.

• @xvw, would it make sense to add Lambda Nantes?
• @rjbou, what about the OCaml workshop in Toulouse?
• same question for Houston Functional Programming meetups, but I'm not sure who to tag.

[xvw]

My goal is to organize more and more OCaml events so I guess that it would make sense ?

[pitag-ha]

There are also events in that section that are not strictly OCaml, e.g. the South England Regional Programming Language Seminar. So, IIUC, it's not only events that are purely OCaml.

[sabine]

The events should include OCaml as a significant part of them. I hope that's the case for everything listed. If not, we have to remove the events that do not meet this criterion.