[Embeddables] Serialized State Only (#215947)

Closes https://github.com/elastic/kibana/issues/205531
Closes #219877.
Closes https://github.com/elastic/kibana/issues/213153
Closes https://github.com/elastic/kibana/issues/150920
Closes https://github.com/elastic/kibana/issues/203130
 
### Overview
The embeddable framework has two types of state: `SerializedState` and
`RuntimeState`.

`SerializedState` is the form of the state when saved into a Dashboard
saved object. I.e. the References are extracted, and state saved
externally (by reference) is removed. In contrast `RuntimeState` is an
exact snapshot of the state used by the embeddable to render.

<b>Exposing SerializedState and RuntimeState was a mistake</b> that
caused numerous regressions and architectural complexities.

This PR simplifies the embeddable framework by only exposing
`SerializedState`. `RuntimeState` stays localized to the embeddable
implementation and is never leaked to the embeddable framework.

### Whats changed
* `ReactEmbeddableFactory<SerializedState, RuntimeState, Api>` =>
`EmbeddableFactory<SerializedState, Api>`
* `deserializeState` removed from embeddable factory. Instead,
`SerializedState` is passed directly into `buildEmbeddable`.
* `buildEmbeddable` parameter `buildApi` replaced with `finalizeApi`.
`buildApi({ api, comparators })` => `finalizeApi(api)`.
* The embeddable framework previously used its knowledge of
`RuntimeState` to setup and monitor unsaved changes. Now, unsaved
changes setup is pushed down to the embeddable implementation since the
embeddable framework no longer has knowledge of embeddable RuntimeState.

### Reviewer instructions
<b>Please prioritize reviews.</b> This is a large effort from our team
and is blocking many other initiatives. Getting this merged is a top
priority.

This is a large change that would best be reviewed by manually testing
the changes
* adding/editing your embeddable types
* Ensuring dashboard shows unsaved changes as expected
* Ensuring dashboard resets unsaved changes as expected
* Ensuring dashboard does not show unsaved changes after save and reset
* Returning to a dashboard with unsaved changes renders embeddables with
those unsaved changes

---------

Co-authored-by: Hannah Mudge <Heenawter@users.noreply.github.com>
Co-authored-by: Nathan Reese <reese.nathan@elastic.co>
Co-authored-by: Nick Peihl <nick.peihl@elastic.co>
Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
Co-authored-by: Catherine Liu <catherine.liu@elastic.co>
Co-authored-by: Ola Pawlus <98127445+olapawlus@users.noreply.github.com>

packages/kbn-optimizer/limits.yml

@@ -90,7 +90,7 @@ pageLoadAssetSize:
   lens: 76079
   licenseManagement: 41817
   licensing: 29004
-  links: 8200
+  links: 9000
   lists: 22900
   logsDataAccess: 16759
   logsShared: 281060