Changes:
- Includes `VERSION` file in source for `jsbundle` derivation
- Includes `BUILD_NUMBER` file and it's generation scripts
- Includes minimal `.git` files to make `git rev-parse --short HEAD` work
- Implements `ignoreVCS` for `mkFilter` to be able to include `.git` files
- Adds missing `git` and `bash` to `buildInputs` for `jsbundle` derivation
- Dropped `bash -c` from Clojure code calling `git`
Signed-off-by: Jakub Sokołowski <jakub@status.im>