Kibana: Branding updates

[alexfrancoeur]

With the upcoming changes in our navigation (https://github.com/elastic/kibana/pull/64018), we'll also have to make some additional branding changes. The proposed updates are listed below.

Welcome page

• [x] Change to: Welcome to Elastic and remove "Your window into the Elastic Stack"

Favicon & Tab title

• [x] Change to: Elastic Cluster logo + “Elastic” as the title

Loading screen

• [x] Change to: Loading Elastic

Splash Screen

• [x] Change to: Welcome to Elastic and remove "Your window into the Elastic Stack"

Primary Logo / masthead

• [x] Change to: Elastic Cluster logo

Log out text

• [x] Change to: You have logged out of Elastic

Full screen mode

• [x] Change to: Exit full screen

Loading newsfeed

• [x] Change to: Elastic Cluster logo

cc: @gchaps for feedback and visibility. @ryankeairns We're still finalizing with the appropriate stakeholders but should have a 👍 by tomorrow.

[alexfrancoeur]

cc: @VijayDoshi

[VijayDoshi]

@alexfrancoeur I went through the document and mostly approved with some minor suggestions.

[alexfrancoeur]

@ryankeairns one quick update from @VijayDoshi . Keep the the cluster logo and remove the Elastic text for the full screen button.

Full screen mode

• [x] Change to: Exit full screen

[alexfrancoeur]

Also, we may want to hold off on merging this PR until https://github.com/elastic/kibana/pull/64018 is in

[gchaps]

Text LGTM.