Add new End-to-End dependency

[mr-suw]

update docker file according to https://github.com/jeremiah-k/meshtastic-matrix-relay/blob/main/docs/E2EE.md for supporting the new end-to-end encryption.

I think just adding the following is sufficient:

Install MMRelay with E2EE support (recommended)

pipx install 'mmrelay[e2e]'

More docker related info regarding E2EE is also given in https://github.com/jeremiah-k/meshtastic-matrix-relay/blob/main/docs/DOCKER.md