Merge branch 'refactor/security_docs_re-org_v5.3' into 'release/v5.3'

refactor(docs): re-organize security docs for better navigation (v5.3)

See merge request espressif/esp-idf!36961

docs/en/security/security.rst

@@ -1,5 +1,5 @@
-Security
-========
+Security Overview
+=================
 
 {IDF_TARGET_CIPHER_SCHEME:default="RSA", esp32h2="RSA or ECDSA", esp32p4="RSA or ECDSA"}