* Use standard lessc and minify CSS using Node.js
This changes the previous nonstandard `lessc` to the official one and
enables CSS minification via the clean-css module.
To build CSS, Node.js is required along with a `npm install` to get the
tools installed locally in node_modules so there is no dependency on
binaries in PATH. Benefits include:
- Allows one to have a standard lessc in PATH.
- Can now use command line switches on lessc.
- Minified CSS brings faster page load times and also has the benefit
of discouraging contributors from editing CSS directly.
To build CSS, Node.js is required along with a `npm install` to get the
tools installed locally based on the information in `package.json`.
The 'make stylesheet' task was modified to run without condition. This
makes it easier to work on the make task itself without having to delete
files.
Also fixes: https://github.com/go-gitea/gitea/issues/2198
* install node, npm and modules on drone
* .PHONY
* use 'minify' to minify CSS
