UI/UX: Fix blockchain-blocks skeleton. (#697)

* Fix blockchain-blocks skeleton.

* Fix blockchain skeleton background.

* Fix mempool blockchain skeleton.

* Add e2e testing.
Add tsconfig.
Fix mempool fit to screen.

* Fix wrong return.
Fix e2e testing.

* Fix blockchainblocks connectionstate.
Add init action to websocket mock.
Add e2e testing for droping websock connection.

* Ref e2e code for websocket connection.
Fix blockchain blocks skeleton.

* Fix state connections.
Remove .only e2e tests.

* Fix mempool blocks skeleton.

* Add fit screen to empty blocks.

frontend/cypress/support/index.d.ts

@@ -0,0 +1,10 @@
+
+/// <reference types="cypress" />
+declare namespace Cypress {
+    interface Chainable<Subject> {
+        waitForSkeletonGone(): Chainable<any>
+        waitForPageIdle(): Chainable<any>
+        mockMempoolSocket(): Chainable<any>
+        changeNetwork(network: "testnet"|"signet"|"liquid"|"bisq"|"mainnet"): Chainable<any>
+    }
+}