Add node version variable to docs (#10620)

Also adjusted other version mentions so go version is always mentioned
as major.minor and node only as major.

Co-authored-by: silverwind <me@silverwind.io>

Makefile

 go-check:
 	$(eval GO_VERSION := $(shell printf "%03d%03d%03d" $(shell go version | grep -Eo '[0-9]+\.?[0-9]+?\.?[0-9]?[[:space:]]' | tr '.' ' ');))
 	@if [ "$(GO_VERSION)" -lt "001011000" ]; then \
-		echo "Gitea requires Go 1.11.0 or greater to build. You can get it at https://golang.org/dl/"; \
+		echo "Gitea requires Go 1.11 or greater to build. You can get it at https://golang.org/dl/"; \
 		exit 1; \
 	fi
 
 	$(eval NODE_VERSION := $(shell printf "%03d%03d%03d" $(shell node -v | grep -Eo '[0-9]+\.?[0-9]+?\.?[0-9]?' | tr '.' ' ');))
 	$(eval NPM_MISSING := $(shell hash npm > /dev/null 2>&1 || echo 1))
 	@if [ "$(NODE_VERSION)" -lt "010000000" -o "$(NPM_MISSING)" = "1" ]; then \
-		echo "Gitea requires Node.js 10.0.0 or greater and npm to build. You can get it at https://nodejs.org/en/download/"; \
+		echo "Gitea requires Node.js 10 or greater and npm to build. You can get it at https://nodejs.org/en/download/"; \
 		exit 1; \
 	fi
 

README.md

 The `build` target is split into two sub-targets:
 
 - `make backend` which requires [Go 1.11](https://golang.org/dl/) or greater.
-- `make frontend` which requires [Node.js 10.0.0](https://nodejs.org/en/download/) or greater.
+- `make frontend` which requires [Node.js 10](https://nodejs.org/en/download/) or greater.
 
 If pre-built frontend files are present it is possible to only build the backend:
 

docs/config.yaml

   version: 1.11.0
   minGoVersion: 1.11
   goVersion: 1.13
+  minNodeVersion: 10
 
 outputs:
   home:

docs/content/doc/advanced/hacking-on-gitea.en-us.md

 
 Next, [install Node.js with npm](https://nodejs.org/en/download/) which is
 required to build the JavaScript and CSS files. The minimum supported Node.js
-version is 10 and the latest LTS version is recommended.
+version is {{< min-node-version >}} and the latest LTS version is recommended.
 
 You will also need make.
 <a href='{{< relref "doc/advanced/make.en-us.md" >}}'>(See here how to get Make)</a>

docs/content/doc/installation/from-source.en-us.md

 
 Next, [install Node.js with npm](https://nodejs.org/en/download/) which is
 required to build the JavaScript and CSS files. The minimum supported Node.js
-version is 10 and the latest LTS version is recommended.
+version is {{< min-node-version >}} and the latest LTS version is recommended.
 
 **Note**: When executing make tasks that require external tools, like
 `make misspell-check`, Gitea will automatically download and build these as
 To build from source, the following programs must be present on the system:
 
 - `go` {{< min-go-version >}} or higher, see [here](https://golang.org/dl/)
-- `node` 10.0.0 or higher with `npm`, see [here](https://nodejs.org/en/download/)
+- `node` {{< min-node-version >}} or higher with `npm`, see [here](https://nodejs.org/en/download/)
 - `make`, see <a href='{{< relref "doc/advanced/make.en-us.md" >}}'>here</a>
 
 Various [make tasks](https://github.com/go-gitea/gitea/blob/master/Makefile)
 The `build` target is split into two sub-targets:
 
 - `make backend` which requires [Go {{< min-go-version >}}](https://golang.org/dl/) or greater.
-- `make frontend` which requires [Node.js 10.0.0](https://nodejs.org/en/download/) or greater.
+- `make frontend` which requires [Node.js {{< min-node-version >}}](https://nodejs.org/en/download/) or greater.
 
 If pre-built frontend files are present it is possible to only build the backend:
 

docs/content/doc/installation/from-source.zh-cn.md

 要从源代码进行编译，以下依赖程序必须事先安装好：
 
 - `go` {{< min-go-version >}} 或以上版本, 详见 [here](https://golang.org/dl/)
-- `node` 10.0.0 或以上版本，并且安装 `npm`, 详见 [here](https://nodejs.org/en/download/)
+- `node` {{< min-node-version >}} 或以上版本，并且安装 `npm`, 详见 [here](https://nodejs.org/en/download/)
 - `make`, 详见 <a href='{{< relref "make.zh-cn.md" >}}'>这里</a>
 
 各种可用的 [make 任务](https://github.com/go-gitea/gitea/blob/master/Makefile)

docs/layouts/shortcodes/min-node-version.html

+{{ .Site.Params.minNodeVersion }}