* Replace "Element" with "Element Web"

- If Element indicates the web application, then it is changed to Element Web.
- If it indicates clients branded with Element such as Element desktop, web, mobile clients, then it is changed to Element clients.
- If it is combined with location sharing functionality, it is not changed.

with other some changes, including:

- Change "app.element.io" anchor link to "https://github.com/element-hq/element-web" on README.md, following other documentation files

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

* Replace "SchildiChat" with "SchildiChat Web"

- If SchildiChat indicates the web application, then it is changed to SchildiChat Web.
- If it indicates clients branded with SchildiChat such as SchildiChat desktop, web, mobile clients, then it is changed to SchildiChat clients.
- If it is combined with location sharing functionality, it is not changed.

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

* Rename configuring-playbook-client-schildichat.md to configuring-playbook-client-schildichat-web.md

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

* Rename configuring-playbook-client-element.md to configuring-playbook-client-element-web.md

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

---------

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>
Co-authored-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

* update http2 config due to deprecation

the previous way to let `http2` follow a `listen` was depracated, it
moved to `http2 on;`

* enable quic and http3

I hope the comments are somewhat understandable. if someone can describe
the `reuseport` part more concise, please do.

Updated the 'nginx reverse-proxy fronting' documentation with a guide for Nginx Proxy Manager, as you can't use the pre-existing nginx matrix.conf