Deploy old versions of core apps to mimic mainnet deployment

[sohkai]

Now that we have multiple live versions of the core Aragon apps' contracts, it would be nice for aragen to also deploy older versions in case someone needed to use an older version than latest.

This should be fairly trivial to achieve; we can use git tags to move the aragon-apps repo to different release tags (correlated with actual mainnet releases) and just release a major version of the apps on each release that had contract changes.

[kernelwhisperer]

💯

This would solve a lot of issues.

Related to aragon/aragon-cli#377

[0xGabi]

Nice! I'll work on this next week

[0xGabi]

Superseded by #99