[Dovecot][Web] imapsync: verify certificates against the source host, make the check optional per source

data/web/lang/lang.en-gb.json

@@ -1545,6 +1545,9 @@
         "source_tenant_hint": "Directory (tenant) ID or a domain of the tenant, e.g. contoso.onmicrosoft.com. It is inserted into the endpoints.",
         "source_scope_cc_hint": "Sources using the client credentials flow are always private to their creator.",
         "source_readonly_hint": "This sync source is shared with you and can only be viewed.",
+        "source_verify_cert": "Verify the server certificate",
+        "source_verify_cert_hint": "For SSL and STARTTLS. Turn off for servers with a self-signed or expired certificate or a certificate that does not match the host.",
+        "source_verify_cert_off": "The server certificate is not verified",
         "copy": "Copy",
         "copied": "Copied to clipboard",
         "source_view": "Show",