Web: Unclear contribution situation

[pascalwengerter]

Steps to reproduce

1. Be interested in contributing
2. Go to contribution guidelines

Expected behaviour

Leave with a clear understanding how contribution works for this repository / owncloud repositories

Actual behaviour

1. In the web repository, there's a broken link to a contribution agreement
2. In the legacy core repository, there's a link to an existing contribution agreement
3. In the new ocis repository, there's no notice of such an agreement at all

Server configuration

Not applicable

Client configuration

Browser: All
Operating system: All

Logs

Not applicable

ownCloud log (data/owncloud.log)

Not applicable

Browser log

Not applicable

[kulmann]

For oCIS the contribution guideline is a simple Fork -> Patch -> Push -> Pull Request as stated in the readme: https://github.com/owncloud/ocis#contributing
We don't need a signed contribution agreement on PRs to oCIS because we're using Apache-2.0 as a license there.

For the web repo I made a PR, which you already know. :-)