Multi-file snippet: content for all blobs is fetched in one request

When querying for the blobs in a snippet, all GraphQL queries are batched into one request. This also includes content for those blobs that are too large to be rendered that leads to the following unwanted side-effects:

• the rendering of all blobs is blocked while this query is in progress even if a blob is only 1 byte
• the query becomes huge if there are a couple of large blobs.

Proposal

1. Disable batching for GraphQL queries in the snippet Vue application
2. Support querying for the content of a particular blob (using the blob's path)