Create postgis template with extensions

[raphink]

This PR allows to automatically create a postgis template and activate postgis extensions on it.

It depends on #521 (whose commit is included here).

[crawlik]

+1 LGTM

[mcanevet]

+1

[underscorgan]

Hi @raphink, could you rebase this against master, add documentation for the updates in postgresql::server::postgis, and squash down to a single commit? Looks like travis was having some issues last time this ran through, but I'm hoping it works better this time. Thanks for the contribution! sorry this got a bit lost.

[underscorgan]

@raphink ping?

[tphoney]

Thanks for the work you have put in to this pull request. However due to inactivity and failing unit tests, no documentation and needs rebased.
This pull request is being closed. If you want to re-submit this pr with the necessary changes, we will look at the new pull request.