Allow specifying importers containers

See merge request memri/pod!156

Fix docker image for run_importer

See merge request memri/pod!154

Update importer run

See merge request memri/pod!153

Importers and Indexers are now Integrators and have a repository property

See merge request memri/pod!152

Update for WhatsApp messages in rustIntegrators

See merge request memri/pod!151

Whatsapp importer

See merge request memri/pod!150

Implement Shared Server (a.k.a. Data Collectives, Shared Pod)

See merge request memri/pod!148

Fix integrators callback address

See merge request memri/pod!149

Disallow group imports

See merge request memri/pod!147

For example:
```
use futures::{compat::Compat01As03, future::BoxFuture, prelude::*};
```

and
```
use std::{
    fmt::{self, Display},
    result,
};
```

Implement insert_tree API

See merge request memri/pod!146

Implement date filtering (efficient sync)

See merge request memri/pod!145

Update readme

See merge request memri/pod!144

Update readme

See merge request memri/pod!143