feat: add api for preparing demo data (#1370)

This PR adds API to populate an empty Parseable
server with demo / dummy data so users get an 
experience of Parseable.

Here are the PRs:

API GET /api/v1/demodata?action=ingest
to ingest 10k records from the script

GET /api/v1/demodata?action=filters
to create saved sqls and saved filters from the script

Author: nikhilsinhaparseable

Cargo.lock

@@ -122,6 +122,7 @@ thiserror = "2.0"
 ulid = { version = "1.0", features = ["serde"] }
 xxhash-rust = { version = "0.8", features = ["xxh3"] }
 futures-core = "0.3.31"
+tempfile = "3.20.0"
 
 [build-dependencies]
 cargo_toml = "0.21"