[Feature Request]: Execution Information Location: retention policy (by count / by days)

### What would you like to happen?

Problem
Execution Information Location keeps accumulating execution records (e.g., log_file location) without built-in retention controls. In long-running production usage this increases disk usage and makes later analysis/navigation slower.

Proposal
Add optional retention settings to Execution Information Location metadata:

Retention by count: keep last N executions per pipeline/workflow (or per location), delete older records automatically.

Retention by age: keep executions for last X days, delete older records automatically.

Option to choose scope:

per “location” (global)

per pipeline/workflow name (recommended)

Acceptance criteria

When retention is enabled, older execution records are removed automatically.

Deletion should be safe: remove only records belonging to the configured location.

Works for “local/log_file” execution information location and any other supported backend.

Retention runs:

on write (after storing a new execution), and/or

as a periodic cleanup task (configurable)

Notes / rationale
This supports production hygiene and avoids external scripts for rotation/cleanup.

### Issue Priority

Priority: 3

### Issue Component

Component: Hop Gui, Component: Metadata

Start with the Hop Gui and Metadata components that define Execution Information Location metadata. Clarify whether retention is scoped per location or per pipeline/workflow, and whether cleanup runs on write or periodically. Done means safely removing only matching older records for local/log_file and other supported backends.

Written by the indexing model from the issue text.