wkhtmltopdf: Also support 'htm' as source_format ('text/html' mimetype maps to both 'htm' and 'html' extensions).

/reviewed-on nexedi/cloudooo!18

using python csv module

latin1 is still supported as a fallback when input csv does not decode
as utf8

Split into several test classes for easier maintainance

no need for test_suite everywhere

The cloudooo test on erp5-master is not able to finish after last erp5.util release: https://nexedijs.erp5.net/#/test_result_module/20180719-86977F42

After fix, there is a cloned test suite and the test is completed: https://nexedijs.erp5.net/#/test_result_module/20180719-781978C2 , but some test fails.

I don't know these particular tests neither if they are failing due to the egg release, but the change in this MR solves the problem with test execution and it is ready to merge.

/reviewed-on nexedi/cloudooo!17

(cherry picked from commit e006854)

(cherry picked from commit 5032914)

/reviewed-on nexedi/cloudooo!14

`cloudooo.handler.yformat.handler` was mainly contributed by
Boris Kocherov. Commit 0bb5fbdc
should have been credited to him.

fix backward compatibily + update test

- source format is html
- destination format is pdf
- conversion_kw is not empty

- keeping backward compatibility
- using getAllowedConversionFormatList
- deprecating getAllowedExtensionList

/reviewed-on nexedi/cloudooo!9

Originaly, the y format (docy, xlsy, ppty) is a file extension that is use by an OnlyOffice document.

An OnlyOffice document is composed by : 

- a file with extension in (docy, xlsy, ppty)
- a separate media folder containing media files (Ex: media/image1.png)

Several problems : 

- Two documents cannot be in the same folder
- How to send / get from Cloudooo to ERP5 ?
- The document cannot be stored easily in ERP5 (embedded files ? seperate images linked to the document by predecessors ??)
- How to download an OnlyOffice document from ERP5 ? How to load it on OfficeJS ?

To solve, we embbed all the files composing the document into one zip (like docx, odt, ...) : 

- Two documents can be in the same folder
- We send / get from Cloudooo as usual with portal transform
- The document can be stored in File data in ERP5 like any other docx document.
- document.getData allows to download the document data and JSZip can be used to extract easily the body in OfficeJS.

To keep backward compatibility, a docy can be : 
- the OnlyOffice document body (`startsWith("DOCY;v2;")`)
- can be a zip file (`startsWith("PK\x03\x04")`) containing one file at the root of the archive + optional media folder

/reviewed-on nexedi/cloudooo!8