Update CONTRIBUTINGs and READMEs for Node and npm versions

Signed-off-by: Florian Hotze <[email protected]>

Author: florian-h05

README.md

@@ -56,11 +56,12 @@ You find the following repository structure:
 
 In most cases, you **don't** need a Java development environment for UI development.
 
-Instead, make sure you have NodeJS 16.14 (HABot: 12.16) or later and npm 8.6 (HABot: 6.14) or later installed.
+Instead, you need NodeJS and npm installed, you'll learn about the required versions later.
 
-
-Then identify in the `bundles` directories where the frontend code is - for instance, for the main UI it is `bundles/org.openhab.ui/web/`.
-Then follow the instructions in the specific add-on's `CONTRIBUTING.md` file to get started. In the main UI's case, it is located in [bundles/org.openhab.ui/CONTRIBUTING.md](https://github.com/openhab/openhab-webui/blob/master/bundles/org.openhab.ui/CONTRIBUTING.md). In many cases it will involve executing some `npm` commands to install dependencies and start a development server.
+Then identify in the `bundles` directories where the frontend code is - for instance, for the Main UI it is `bundles/org.openhab.ui/web/`.
+Then follow the instructions in the specific add-on's `CONTRIBUTING.md` file to get started, e.g. install the correct versions of NodeJS and npm.
+For Main UI, it is located in [bundles/org.openhab.ui/CONTRIBUTING.md](https://github.com/openhab/openhab-webui/blob/master/bundles/org.openhab.ui/CONTRIBUTING.md).
+In many cases it will involve executing some `npm` commands to install dependencies and start a development server.
 
 However, if you want to compile the final `.jar` add-ons, we have assembled some step-by-step guides for different IDEs on our developer documentation website:
 

bundles/org.openhab.ui.basic/CONTRIBUTING.md

@@ -1,6 +1,10 @@
 ## Contributing
 
-Javascript linting, compressing and LESS compilation is handled through Gulp. Therefore, please run `gulp` instead of changing compressed CSS/JS manually. Default Gulp task will also check the code using ESLint.
+You need NodeJS 18.17.0 or later and npm 9.8.1 or later installed.
+
+Javascript linting, compressing and LESS compilation is handled through Gulp.
+Therefore, please run `gulp` instead of changing compressed CSS/JS manually.
+Default Gulp task will also check the code using ESLint.
 
 Installing build dependencies:
 

bundles/org.openhab.ui.habot/CONTRIBUTING.md

@@ -0,0 +1,3 @@
+# Contributing to HABot
+
+You need NodeJS 12.16 or later and npm 6.14 or later installed.

bundles/org.openhab.ui.habpanel/CONTRIBUTING.md

@@ -14,8 +14,10 @@ redirect you, if necessary.
 
 ## Build Environment
 
-It is assumed you have ```npm```, ```bower``` and ```gulp``` available; if not,
-check their respective docs.
+You need NodeJS 16.14 or later and npm 8.6 or later installed.
+
+It is assumed you have `npm`, `bower` and `gulp` available;
+if not, check their respective docs.
 
 To build the Javascript part of HABPanel, navigate to the ```web/``` subfolder, then:
 1. Run ```npm install```

bundles/org.openhab.ui/CONTRIBUTING.md

@@ -8,7 +8,9 @@ The repository for web user interfaces, including this project, is located at <h
 
 This project is built using [Vue.js](https://vuejs.org/), [webpack](https://webpack.js.org/) and [Framework7](https://framework7.io).
 
-You need Node 18.18.0 or later and npm 9.8.1. Change to the `web` directory, gather the necessary dependencies with `npm install` then the scripts below will be available.
+You need Node 18.18.0 or later and npm 9.8.1 or later installed.
+
+Change to the `web` directory, gather the necessary dependencies with `npm install` then the scripts below will be available.
 
 ## NPM Scripts