Add a document describing how to assemble setup for the
Smart Panel blueprint, how to build images for Avenger96
and Nitorgens, how to flash them and configure Home Assistant.

Add images with HA UI configuration examples and photo of
the assembled setup.

Signed-off-by: Wojciech Zmuda <wojciech.zmuda@huawei.com>

The correct from is "All Scenarios OS" as opposed to "All Scenario OS".
This change also replaces a reference to OHOS.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

This relies on the plantuml plugin/module so it also includes the
required extension and to simplify that, we switch to using a `conf.py`
file.

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

Acronym looks good in some places but in sentences the full name is more
readable.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

External repositories for various distributions are left unchanged.

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

Show Dashboard/SmartHome demo setup on a puml diagram.

Signed-off-by: Zbigniew Bodek <zbigniew.bodek@huawei.com>

- Add building and flashing guidelines for SmartHome demo
  endpoints

Signed-off-by: Zbigniew Bodek <zbigniew.bodek@huawei.com>

- Remove demo description and HOWTO from meta-ohos-demo README.md
- Improve building guidelines in the smart-panel.rst
  Reference to building an image for Avenger96 + explicit command
  for building dashboard demo.

Signed-off-by: Zbigniew Bodek <zbigniew.bodek@huawei.com>

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>

Signed-off-by: Zygmunt Krynicki <zygmunt.krynicki@huawei.com>

Signed-off-by: Andrei Gherzan <andrei.gherzan@huawei.com>