Doc table panel

[rashidkpc]

Closes #2024

What this does now:

• Adds support for saved searches as document tables on the dashboard.
• Adds type key to dashboard panel schema to support things other than visualizations. Can use this for input panels in the future
• Added a configurable edit destination for panels, eg #visualize/edit for visualizations, #/discover for searches
• Adds a tab called Searches to the panel adding dialog
• Creates a reusable doc-table directive that can visualize an array of hits
• Moves table-row and table-header into the doc-table directive and out of discover.js
• Allows for sorting changes
• Removes a slow cloneDeep in fetch.js
• Removes a buggy flatten routine that didn't know the mapping.
• Lets table-row do the flattening/formatting if it hasn't already been done. Caches on $$_flattened and $$_formatted
• Removes the timefield attribute we'd been passing around since indexPattern already has it.

What it will not do:

1. Replace the table code in discover with doc-table. There's a bunch of discover changes in Timefilter Auto Refresh - Closes "Support for auto-refresh #1845" #2196. They do share the table-row and table-header code, which is good, so it only the table element wrapper that is unique to discover. After Timefilter Auto Refresh - Closes "Support for auto-refresh #1845" #2196 is merged we can see about using doc-table in discover
2. Implement filtering.
3. Allow adding/removing columns from the dashboard, this must be done from discover. Feels like a phase 2 item since it requires a new field picker, and figuring out dashboard-specific panel option persistence

I'm happy todo 1. and 2. above as separate issues, this pull was just getting too big.

[huangchaosuper]

looks good. which is my needed.

[simianhacker]

Infinite scrolling is not working.

[rashidkpc]

@simianhacker got rid of the infinite scrolling on the dashboard, added paginate controls to the top and bottom of the panel.

[simianhacker]

LGTM