This is a combination of 4 commits.
Omitted are 2246f478 and
7340872a that replace the Calc code with
calling the new SvNumberFormatter functions.

introduce SvNumberFormatter::FillKeywordTableForExcel()

... to conflate the places that do this on their own.

(cherry picked from commit b5554804)

use proper case "General" keyword

... Excel doesn't seem to care though.

(cherry picked from commit ea1db935)

introduce SvNumberFormatter::GetFormatStringForExcel()

Taking implementation from sc/source/filter/excel/xestyle.cxx
GetNumberFormatCode(), slightly modified to ensure valid conversion and
force en-US locale data. Also don't unnecessarily convert if format is
for system locale and system locale is en-US.

(cherry picked from commit 2011b541)

Resolves: tdf#96072 export Chart format codes in Excel notation

As for the change in chart2/qa/extras/chart2export.cxx
Chart2ExportTest::testAxisNumberFormatXLSX() unit test: also Excel
writes string parts of format codes quoted, including minus sign in
negative subformat.

(cherry picked from commit 509cfa40)

3697a808d8fee2417f0b0e03dba2b94ceea133dd
9223eaa655132b4106a35c94cb0005559d7575b1
201bb012df818129cbc65de0eee8eca59e57d829

Change-Id: Idde2173780e0515ad982b4be46fc4df23a7577ad
Reviewed-on: https://gerrit.libreoffice.org/20249Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Tested-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
(cherry picked from commit 446a3a06)