Package php5.6 and php7.0 so we can still provide them after sury stops providing, fixes #1448

[rfay]

The Problem/Issue/Bug:

OP #1448: deb.sury.org will no longer be providing php5.6 and php7.0, but our users will still want those.

How this PR Solves The Problem:

• Put the php5.6 and php7.0 .deb packages on bintray as tarballs
• Download them during the docker build and install as files.

Manual Testing Instructions:

All this really requires is checking to make sure that php5.6 and php7.0 can still be used.

It would be good to check on xdebug on all versions

Automated Testing Overview:

Existing tests should catch regressions.

Related Issue Link(s):

OP #1448

Release/Deployment notes:

This requires having the old package tarballs in a safe location so we can repeat this build in the future. I put it at bintray (https://dl.bintray.com/drud/oldphptarballs) but I'm not totally sold that that's the best place. Suggestions are welcome.

[unn]

Maybe this is a documentation task, but it would be nice if we could inform the user that these versions of PHP are at end of life and are likely not compatible with many hosting providers.

# The php_versions below contain several options for your development requirements, however, PHP 5.6 and 7.0 are at end of life (eol) and are deprecated. You should not begin a new project or attempt to maintain an old project on these versions. You will not be able to host your project on these versions of PHP.

php_version: "5.6-eol"  # PHP version to use, "5.6-eol", "7.0-eol", "7.1", "7.2", "7.3"

[andrewfrench]

I can confirm that versions 5.6 and 7.0 are still configurable using the changes here. I don't necessarily think we should block this PR on it, but I think @unn's comment about communicating EOL/non-preferred PHP versions is a good idea.

[rfay]

I've tested this on all PHP versions and it seems to work fine. The one question that I have is whether we should be installing those unversioned php items (xdebug, apcu) at all, or if we're installing them, should they be installed before the regular PHP installs. Either way, we may get a situation in the future where php-xdebug doesn't work with old PHP.

[rfay]

I tested this without the unversioned packages and it seems to work fine. Pushed that in.

Now we'll close this PR until further need because as noted in #1448 (comment), Sury has relented and is going to keep 5.6 and 7.0 in the repo for now.