Update all Katacoda scenarios to run on Kubernetes 1.18, with
a 2 node cluster.

Fix some issues in the tasks and runs scenarios that seem to have
been undone in rebases before they were merged.

Update the Dashboard scenario to run the latest Pipeline and
Dashboard versions at time of writing.

Remove the use of the ingress in the Dashboard scenario since
it appears unstable on Katacoda with kubernetes 1.18. Using a
port-forward is sufficient for this scenario.

Add a Katacoda scenario that can act as a playground for users
to experiment with Tekton in a sandbox environment.

This environment provides a 2-node Kubernetes cluster with the
following projects installed:
- Pipelines v0.14.3
- Dashboard v0.8.2
- CLI v0.11.0

Typical startup time is <1minute, but may take 2 or 3 minutes
in some cases. The installation should not require any manual
steps by the user.

Katacoda supports linking to images in the assets folder. Update our
existing links to use this approach instead of using the GitHub 'raw'
URLs as this gives us greater portability for the tutorials and ensures
the correct version of the images is loaded even if we stop loading content
from the `master` branch in future.

- Moving the code from the decentralized to the centralized
- Create .vimrc in the background to cut down noise in the terminal
- Add a short delay before calling launch.sh to avoid intermittent failures with launch.sh not being ready
- Fix pipeline definition to ensure deploy runs after build
- Fix `kubectl expose` command since there's no deployment involved, just a pod
- Fix some lingering bad PipelineResource versions
Signed-off-by: NJJ Asghar <jjasghar@gmail.com>
Co-authored-by: Nmichaelawyu <michaelawyu@google.com>
Co-authored-by: NAlan Greene <alangree@ie.ibm.com>

- Moved over Brandow Walker's dashboard tutorial
- Created the basic pipeline tutorial
Signed-off-by: NJJ Asghar <jjasghar@gmail.com>
Co-authored-by: NBrandon Walker <bcwalker@ibm.com>

As per user guide https://www.katacoda.community/git-repository-structure.html#scenarios
add a katacoda.yaml so that we may store katacoda scenarios in a
dedicated folder in the website folder.