* 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

* Basic VSCode configuration for building and debugging

* Fix building and debugging in Windows

* Move to contrib folder and add instructions

Creation of release branch before end of release dev and releases candidates + follow semver semantic (minor, patch)

* Clarify Translation Process. Also fix branch names

* Update CONTRIBUTING.md

* Use MAINTAINERS file in repository because teams are not publicly available

* Use relative link

* Add import-styleguide to Contributing.md

Question: should we group all `code.gitea.io`-packages together as local imports? (including `code.gitea.io/sdk` and `code.gitea.io/git` etc)

* reorg

* be specific FFS

Signed-off-by: Thibault Meyer <meyer.thibault@gmail.com>

Signed-off-by: Morgan Bazalgette <the@howl.moe>

* CONTRIBUTING.md: link to "Faster reviews" document

* CONTRIBUTING.md: small fixes

Closes #178

Use a list for owners (nitpick response)