Connection timeout

[opichon]

I've added a variable named connection_timeout with a default value of 2m.

Rationale: we are installing docker ce via the user_data var. This can take up to several minutes more than the 2m timeout that was hard-coded in the modules. Then terraform keeps spinning without end.

By configuring the connection timeout via a variable, users can set it to whatever value works for them.

[thojkooi]

Thanks @opichon 👍