[docs] big bang update (#348)

* [docs] big bang update

* Simplified polluted README.md by moving parts to the documentation
* Removed duplicates with `pymdownx.snippets` extension
* Enabled code copy
* Extended "Getting Started"
* Added "Monitoring" page
* Separated "Upgrade" page
* Added default config yaml to docs

Signed-off-by: Dmytro Bondar <git@bonddim.dev>

* Update sources.md

Co-authored-by: h44z <christoph.h@sprinternet.at>

---------

Signed-off-by: Dmytro Bondar <git@bonddim.dev>
Co-authored-by: h44z <christoph.h@sprinternet.at>

docs/documentation/getting-started/sources.md

@@ -0,0 +1,24 @@
+To build the application from source files, use the Makefile provided in the repository.
+
+## Requirements
+
+- [Git](https://git-scm.com/downloads)
+- [Make](https://www.gnu.org/software/make/)
+- [Go](https://go.dev/dl/): `>=1.23.0`
+- [NodeJS with npm](https://nodejs.org/en/download): `node>=18, npm>=9`
+
+## Build
+
+```shell
+# Get source code
+git clone https://github.com/h44z/wg-portal -b ${WG_PORTAL_VERSION:-master} --depth 1
+cd wg-portal
+# Build the frontend
+make frontend
+# Build the backend
+make build
+```
+
+## Install
+
+Compiled binary will be available in `./dist` directory.