Add changelog entry for defi overview

Fix #921
Fix #1099

docs/changelog.rst

@@ -2,6 +2,7 @@
 Changelog
 =========
 
+* :feature: `921` A new DeFi overview component is added. There the user can get an overview of all their balances across all DeFi protocols. For protocols that are supported further the user can click and be taken to the protocol specific page to see more details and historical accounting for that protocol.
 * :feature: `1160` The Accounts & Balances page layout has been updated to increase usability. It is now split across three sub-pages: Blockchain Balances, Exchange Balances, Manual Balances (includes Fiat Balances). Exchange Balances is a new page where you will be able to see all of your asset balances for each connected exchange (previously this was only accessible from the Dashboard by clicking on an exchange). 
 * :bug: `1140` The Accounts column in "Blockhain Balances" is now correctly sorted by label (if it exists) or the account address.
 * :bug: `1154` Tag filtering in "Manual Balances" within Accounts & Balances now works correctly if any balances do not have any tags assigned.