Add support for migrating qdrant collections

[olirice]

What kind of change does this PR introduce?

Adds a vec2pg qdrant migrate command for migrating qdrant collections to postgres

Tasks:

• implement migrate command
• enable API key passed as an env var
• test using local docker setup
• minimal docs in README
• test on CI
• complete docs
• measure throughput on qdrant hosted

[gregnr]

Nice work 👍

[gregnr]

Suggested change

	Then we can call `vec2pg qdrant migrate` passing our values. You can supply all parameters directly to the CLI, but its a good idea to pass the Qdrant API Key (QDRANT_API_KEY) and Supabase connection string (POSTGRES_CONNECTION_STRING) as environment variables to avoid logging credentials to your shell's history.
	Then we can call `vec2pg qdrant migrate` passing our values. You can supply all parameters directly to the CLI, but it's a good idea to pass the Qdrant API Key (QDRANT_API_KEY) and Supabase connection string (POSTGRES_CONNECTION_STRING) as environment variables to avoid logging credentials to your shell's history.