first steps to reduce npm package size & deliver generated docs

- updated .gitignore
- created .npmignore
- created new scripts for docs and publish prepare in package.json

.gitignore

@@ -22,6 +22,7 @@ bower_components/
 // Docs
 Gemfile.lock
 docs/_site
+docs_html/
 .jekyll-cache/
 .jekyll-metadata
 

.npmignore

@@ -0,0 +1,2 @@
+/docs/
+/plugins/

package.json

@@ -12,10 +12,14 @@
     "css-minify": "cleancss --level 1 --source-map --source-map-inline-sources --output dist/css/adminlte.min.css dist/css/adminlte.css",
     "compile": "npm-run-all --parallel js css",
     "dev": "npm-run-all --parallel watch sync",
+    "docs-serve": "cd docs/ && bundle exec jekyll serve",
+    "docs-compile": "cd docs/ && bundle exec jekyll build -d ../docs_html",
+    "docs-clean": "cd docs/ && bundle exec jekyll clean -d ../docs_html",
     "js": "npm-run-all --sequential js-compile js-minify",
     "js-compile": "rollup --config build/config/rollup.config.js --sourcemap",
     "js-minify": "terser --compress typeofs=false --mangle --comments \"/^!/\" --source-map \"content=dist/js/adminlte.js.map,includeSources,url=adminlte.min.js.map\" --output dist/js/adminlte.min.js dist/js/adminlte.js",
     "production": "npm-run-all --sequential compile plugins",
+    "prepare": "npm-run-all --sequential compile plugins docs-clean docs-compile",
     "plugins": "node build/npm/Publish.js -v",
     "sync": "browser-sync start --server --files *.html pages/ dist/",
     "watch": "npm-run-all --parallel watch-css watch-js",