Linked Time: Enable Linked Time (#6137)

## Motivation for features / changes
This feature is complete and we would like people to use it

## Technical description of changes
The Linked Time feature is controlled by 4 feature flags:
* `enabledScalarDataTable`
* `enabledLinkedTime`
* `allowRangeSelection`
* `enabledProspectiveFob`


## Screenshots of UI changes
Settings Panel:

![image](https://user-images.githubusercontent.com/78179109/211650399-ad62bb7f-297a-4724-9d43-d20e65c8d965.png)

Prospective Fob:

![image](https://user-images.githubusercontent.com/78179109/211650663-e935c18c-a1de-4e51-acb6-28b2b34e3c67.png)

Data Table with Range Selection:

![image](https://user-images.githubusercontent.com/78179109/211650966-318c3097-f1d7-4827-a35e-1ff17249cb96.png)

## Detailed steps to verify changes work correctly (as executed by you)
1) Start TensorBoard
2) Navigate to `localhost:6006` (Note the lack of feature flags)
3) Ensure the settings panel contains the step selection, range
selection, and linked time checkboxes
4) Hover a scalar card X Axis
5) Assert a fob with a border appears
6) Click that fob
7) Assert a permanent fob is created there
8) Assert the table appears on that card
9) Assert you can create a second fob in the same way as the first
10) Click the "Link By Step" checkbox in the settings panel
11) Assert the step selectors on all the fobs jump to the same steps


CC: [japie1235813](https://github.com/japie1235813),
[bmd3k](https://github.com/bmd3k)

Author: rileyajones

tensorboard/webapp/feature_flag/store/feature_flag_metadata.ts

@@ -74,12 +74,12 @@ export const FeatureFlagMetadataMap: FeatureFlagMetadataMapType<FeatureFlags> =
       parseValue: parseStringArray,
     },
     enabledLinkedTime: {
-      defaultValue: false,
+      defaultValue: true,
       queryParamOverride: 'enableLinkedTime',
       parseValue: parseBoolean,
     },
     enabledScalarDataTable: {
-      defaultValue: false,
+      defaultValue: true,
       queryParamOverride: 'enableDataTable',
       parseValue: parseBoolean,
     },
@@ -116,12 +116,12 @@ export const FeatureFlagMetadataMap: FeatureFlagMetadataMapType<FeatureFlags> =
       parseValue: parseBoolean,
     },
     allowRangeSelection: {
-      defaultValue: false,
+      defaultValue: true,
       queryParamOverride: 'allowRangeSelection',
       parseValue: parseBoolean,
     },
     enabledProspectiveFob: {
-      defaultValue: false,
+      defaultValue: true,
       queryParamOverride: 'enableProspectiveFob',
       parseValue: parseBoolean,
     },