feat(widgetDriver): Add to-device encryption support

[toger5]

This is a rebased version of: #4992

It adds:

• add temp to-device encryption methods that should be part of the crypto crate. (they are in the submodule of widget::matrix::to_device_crypto which will be removed once the same methods are available through the matrix sdk crypto crate.

Todos:

• Decide if we really want to simplify to-device sending to NOT include a encryption flag and instead hide all unencrypted to-device from the widget.
• remove the submod: to_device_crypto

• Public API changes documented in changelogs (optional)

Signed-off-by: