Collective-tablepage

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- Do not display selection checkbox if I can't delete a row
[keul]
- Raise lifecycle events properly when creating files
[keul]
- New field type: "Files", for uploading a set of files to
be rendered in the same cell
[keul]
- Labels inside the table are now supported
[keul]
- New view for displaying data on multiple tables
[keul]
- New field type: "Link", for inserting an URL or an internal
reference
[keul]
- CSV export done by backend get UUIDs when applicable
[keul]
- CSV import now validate data: do not import every text you
read from the file
[keul]
- CSV import now transform URL/path to valid content uuids
[keul]

----------------

- Different versioning message when a row is changed
or modified [keul]
- Added missing versioning attempt when using CSV upload
[keul]
- Fixed a performance/security problem: data inside text cells
were transformed to HTML without any check (and this was also
*really* slow)
[keul]
- Can now delete multiple (or all) rows
[keul]
- CSV import is not importing anymore inside wrong colum when an
unknow header is found
[keul]

----------------

- Fixed missing translations [keul]
- Do not display "download as CSV" for empty tables [keul]
- Added an option for choosing when display headers [keul]
- Handle loading of duplicate file id: file is not loaded twice but
same reference is kept [keul]
- Do not display "Edit table" or row's commands if no configuration
has been set [keul]

------------------

- fixed encoding error on columns headers [keul]
- fixed encoding error on editing rows [keul]

------------------

- Fixed UnicodeDecodeError problem with non-ASCII chars [keul]

----------------

- Initial release