[epic] eliminate the need to specify the catalog template type in render-template

[grokspawn]

We can reduce the level of knowledge that opm users need to have about our supported catalog templates if we require an explicit schema for each.

Steps to accomplish this:

• [ ] #1331
• [ ] #1336
• [ ] #1332 (for e.g. [verb] [file(s)] [options]) right now basic/semver templates already follow this format, but composite template with its two required imports does not presently
• [ ] #1333
• [ ] #1334