Fix setup issues for running with cog

[e-cal]

Addresses all the currently open issues for running with cog locally.

• add missing VAE weights to download_weights.py
• add missing extensions (pegged to working versions) to launch_utils.py
• add hack to fix broken clip version (should probably just peg clip to a working version but idk what version works)
• update README to recommend just using download_weights.py to setup the project since with these changes it seems complete now