Add various polish to Conduwuit

https://github.com/Virkkunen and I have been working on the same feature
simultaneously.

This patch adds my additional independent work on top of his changes.

Notable changes here compared to Virkkunen's original work:

- renaming config-related variables (`matrix_conduwuit_*` ->
  `matrix_conduwuit_config_*`). This is consistent with other roles (and
  better), but deviates from how the Conduit role was implemented.

- using a full configuration sample from https://conduwuit.puppyirl.gay/configuration.html
  instead of using the old Conduit config file template

- introducing configurability for more Conduwuit config settings, to support easy registration, etc.

- removing configuration settings that Conduwuit does not support
  anymore (e.g. `max_concurrent_requests`)

- cross-linking docs pages for Conduit and Conduwuit

- a Conduwuit docs page which is much improved compared to the old
  Conduit one

- REAMDE updates

README.md

@@ -52,6 +52,7 @@ The homeserver is the backbone of your Matrix system. Choose one from the follow
 | ---- | -------- | ----------- | ------------- |
 | [Synapse](https://github.com/element-hq/synapse) | ✅ | Storing your data and managing your presence in the [Matrix](http://matrix.org/) network | [Link](docs/configuring-playbook-synapse.md) |
 | [Conduit](https://conduit.rs) | ❌ | Storing your data and managing your presence in the [Matrix](http://matrix.org/) network. Conduit is a lightweight open-source server implementation of the Matrix Specification with a focus on easy setup and low system requirements | [Link](docs/configuring-playbook-conduit.md) |
+| [Conduwuit](https://conduwuit.puppyirl.gay/) | ❌ | Storing your data and managing your presence in the [Matrix](http://matrix.org/) network. Conduwuit is a fork of Conduit. | [Link](docs/configuring-playbook-conduwuit.md) |
 | [Dendrite](https://github.com/element-hq/dendrite) | ❌ | Storing your data and managing your presence in the [Matrix](http://matrix.org/) network. Dendrite is a second-generation Matrix homeserver written in Go, an alternative to Synapse. | [Link](docs/configuring-playbook-dendrite.md) |
 
 ### Clients