Point to new website for developer docs & contributing guidelines. (#3)

* Point to developer documentation for contributing guidelines

* README.md

* Update funding section per new website

CONTRIBUTING.md

@@ -0,0 +1,13 @@
+# Contributing
+
+**Contributors to BrainGlobe are absolutely encouraged**, whether to fix a bug, develop a new feature, or add a new atlas.
+If you would like to contribute, please take a look at our [developer documentation](https://brainglobe.github.io/new-website/developers/index.html).
+
+There are many BrainGlobe repositories, so it may not be obvious where a new contribution should go.
+If you're unsure about any part of the contributing process, please get in touch.
+The best place is to start a new discussion on the [image.sc forum](https://forum.image.sc/tag/brainglobe).
+If you tag your post with `brainglobe` (and optionally a specific tool, e.g. `cellfinder`) we will see your question and respond as soon as we can.
+
+If you have a query about contributing to a specific tool, please do raise an issue on the relevant GitHub page.
+If it's not the correct repository (e.g. `cellfinder` vs `cellfinder-core`), don't worry, we can move it to the relevant repository later.
+If for any reason, you'd rather not reach out in public, feel free to email Adam Tyson, one of the core developers.

README.md

@@ -19,13 +19,11 @@ We have three aims:
 - Build a community of neuroscientists and developers to share knowledge, build software and engage
   with the scientific, and open-source community (e.g. by organising hackathons).
 
-The BrainGlobe project is generously supported by the Sainsbury Wellcome Centre and the Institute of Neuroscience, Technical University of Munich, with funding from the Chan Zuckerberg Initiative, Wellcome, the Gatsby Charitable Foundation and the Munich Cluster for Systems Neurology - Synergy.
+### [**Funding**](https://brainglobe.info/funders.html#funders) Information
 
-<p>
-<img src='https://brainglobe.info/images/SWC.png' width="150">
-<img src='https://brainglobe.info/images/TUM.png' width="150">
-<img src='https://brainglobe.info/images/CZI.png' width="150">
-</p>
+The BrainGlobe project is only possible due to grant funding and the generous support of host institutions, whose information [can be found on this website](https://brainglobe.info/funders.html#funders).
+
+---
 
 ## Installation
 
@@ -34,3 +32,8 @@ The `brainglobe` package can be installed from [PyPI](https://pypi.org/project/b
 pip install brainglobe
 ```
 Alternatively, you can download the source from [PyPI here](https://pypi.org/project/brainglobe/#files).
+
+## Contributing
+
+**Contributors to BrainGlobe are absolutely encouraged**, whether to fix a bug, develop a new feature, or add a new atlas.
+If you would like to contribute, please take a look at our [developer documentation](https://brainglobe.info/developers/index.html).