Allow opting out of component upgrades via amphora settings

[elgreg]

Is your feature request related to a problem? Please describe.

Upgrades, while convenient, are a bit of an anti-pattern. They write back to the database on a read. We generally try to avoid this kind of behavior and would like to just upgrade our components manually using migration scripts.

Describe the solution you'd like

Allow for a config setting that will let us opt-out of using upgrades.

[james-owen]

Using upgrade files is optional, but yes I get it--the pattern is a bit of a footgun. I think code-wise we'd just have to add a check here https://github.com/clay/amphora/blob/master/lib/services/models.js#L69. It's probably more important to update the documentation so the tradeoffs and pitfalls are clear.

[elgreg]

Thanks @james-owen I was actually going to put it in the upgrade.init function if it's all the same. I can send up a PR today as I got it running locally.

Agreed re: documentation. We had a few issues - one was semver - that 1.11 is not higher than 1.9. I think there's also an issue where a 1.0 in yaml somehow gets turned into an integer and then doesn't match the version number that is stored (1.0) so the component always wants to upgrade. Having functionality to turn it off is kind of a cop-out for us b/c we already have so many upgrade files. Ån alternative for us would be to just go in and remove them all. :)