Added 1.7.1 release notes for refs #23483.
Forwardported 1.4.16 release notes.
Fixed #23461 -- Added EMAIL_TIMEOUT setting
Fixed #23466 -- Removed seconds from all locale time output formats.
Fixed #23397 -- Stripped whitespace from base64 during chunking

This insures the actual base64 content has a length a multiple of 4.
Also added a test case for the failure.
Factorized create_index_sql expression
Fixed broken link in 1.7 release notes.