Do not require users to install precomputed library

[AntonPetrov]

There are several things to consider:

• Bundle Rfam and CRW models into 2 files (all.cm) and use cmfetch when individual models are needed
• Commit all.cm to git or use git LFS
• Some applications do not require any precomputed models at all (for example, generating templates locally or the template-free mode). One could create a slim version of the docker image that would be much smaller.