Removed unused seldon analytics variables and updated docs

[axsaucedo]

• Fixes seldon-core-analytics should not use hostPort #1539
• Adds small heads up that all parameters from analytics charts can be overriden
• Merged the custom metrics page into the general prometheus

[seldondev]

Thu Mar 26 20:17:45 UTC 2020
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-1620/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1620 --build=2

[seldondev]

Thu Mar 26 20:18:04 UTC 2020
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-1620/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1620 --build=1

[RafalSkolasinski]

/lgtm
/approve

[axsaucedo]

/approve

[seldondev]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: axsaucedo, RafalSkolasinski

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• OWNERS [axsaucedo]

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[seldondev]

Sun Mar 29 21:38:46 UTC 2020
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-1620/4.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1620 --build=4

[seldondev]

Sun Mar 29 21:38:49 UTC 2020
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-1620/3.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-1620 --build=3