[SPARK-21675][WebUI]Add a navigation bar at the bottom of the Details for Stage Page

[yaooqinn]

What changes were proposed in this pull request?

1. In Spark Web UI, the Details for Stage Page don't have a navigation bar at the bottom. When we drop down to the bottom, it is better for us to see a navi bar right there to go wherever we what.
2. Executor ID is not equivalent to Host, it may be better to separate them, and then we can group the tasks by Hosts .

How was this patch tested?

manually test

Please review http://spark.apache.org/contributing.html before opening a pull request.

[ajbozarth]

Though I think these should have been separate PRs both these changes LGTM, I'm not sure why the original choice was to only display the pagination nabber at the top and though I'm not usually a fan of adding more column, I think separating these two should be fine.

[yaooqinn]

test this please

[yaooqinn]

@ajbozarth do we need another pr to separate these? if necessary, I will do that.

[ajbozarth]

Since they're both small and this is already open I'd say leave it, unless someone ends up having issues with one of the fixes

[srowen]

@ajbozarth thanks as ever for reviewing the UI changes. I'm OK with it too if tests pass

[SparkQA]

Test build #3886 has finished for PR 18893 at commit eaf5e52.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[srowen]

Merged to master