Allow feedback for routers and update router examples

[ukclivecox]

What this PR does / why we need it:

• Ensure Feedback is sent to Routers
• Adds a notebook for epsilon greedy router
• Updates routers case study

Which issue(s) this PR fixes:

Fixes #2827

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[review-notebook-app]

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[seldondev]

Thu Jan 21 18:28:33 UTC 2021
The logs for [lint] [2] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2865/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2865 --build=2

[seldondev]

Thu Jan 21 18:28:42 UTC 2021
The logs for [pr-build] [1] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2865/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2865 --build=1

[axsaucedo]

Looks good!
/approve

[seldondev]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: axsaucedo

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[seldondev]

Tue Jan 26 13:26:04 UTC 2021
The logs for [lint] [4] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2865/4.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2865 --build=4

[seldondev]

Tue Jan 26 13:26:25 UTC 2021
The logs for [pr-build] [3] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2865/3.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2865 --build=3