Add new `fileScanners.scanTimeout` config value

[PE39806]

Is your feature request related to a problem? Please describe.

Implementation of BaseFileScanningConnector's scan method should have and use a configurable timeout option in case the service becomes unresponsive which would currently cause a scan to hang indefinitely.

Describe the solution you would like

Add a new connectors.fileScanners.scanTimeout: number value config.ts, used to control the maximum number of seconds that a scan should be awaited before timing out.
A possible implementation for the scan implentation(s) could be:

function delay(ms: number) {
   return new Promise((_, reject) => {
      setTimeout(() => reject(new Error('Timeout exceeded')), ms);
   });
}

// ...

await Promise.race([delay(config.connectors.fileScanners.scanTimeout * 1000), someScanFunction()]);

Describe alternatives you have considered

An alternative to the above could be to add a new BaseFileScanningConnector._scan method and change BaseFileScanningConnector.scan to call this e.g.

function delay(ms: number) {
   return new Promise((_, reject) => {
      setTimeout(() => reject(new Error('Timeout exceeded')), ms);
   });
}
// ...

export abstract class BaseFileScanningConnector {
  async scan(file: FileInterface): Promise<FileScanResult[]> {
    return await Promise.race([delay(config.connectors.fileScanners.scanTimeout * 1000), this._scan(file)]);
  }
  abstract _scan(file: FileInterface): Promise<FileScanResult[]>

  //...
}

However we do not currently enforce scan to be async so I am unsure on this approach in case there are synchronous BaseFileScanningConnector implementaitons.