Add support for manually adding any-to-any link column in table lists

[Nicklas Nordborg]

In ticket #1950, support for filtering on any-to-any links was added to the core. However, getting the columns into the table lists was left for extensions to implement.

It would be nice if it was possible to manually add columns directly from the web interface. It would be somewhat similar to the parent/child column functionality implemented in #2202 and #2218.

[Nicklas Nordborg]

In 7850:

References #2222: Add support for manually adding any-to-any link column in table lists

Implemented an extension that scan for column definitions that use the pattern |linkName|ITEMTYPE|property and automatically create column definitions based on the information. Filtering was supported since before (#1950).

[Nicklas Nordborg]

In 7851:

References #2222: Add support for manually adding any-to-any link column in table lists

Added a simple dialog for adding any-to-any columns. It is enabled on all lists by default and should be disabled in places were it is not supported (such as lists that mix different kinds of items).

[Nicklas Nordborg]

In 7852:

References #2222: Add support for manually adding any-to-any link column in table lists

Implemented a function for remembering the most recently used item types when adding a column. The most recent types are then displayed first in the selection list.

[Nicklas Nordborg]

In 7853:

References #2222: Add support for manually adding any-to-any link column in table lists

Implemented a function for generating a list of presets from existing any-to-any links. The current table list context (including active filters) is used for sampling a random number items that the current user has access to and then those items are used for checking links.

[Nicklas Nordborg]

In 7854:

References #2222: Add support for manually adding any-to-any link column in table lists

Removed debug output.

[Nicklas Nordborg]

In 7855:

References #2222: Add support for manually adding any-to-any link column in table lists

Added support for enabling the "File viewer" extension in any-to-any links that are targeting a file item.

[Nicklas Nordborg]

In 7864:

References #2218 and #2222. Suppress compilation warnings for creating a raw array type.

[Nicklas Nordborg]

In 7867:

References #2222: Add support for manually adding any-to-any link column in table lists

Hide the "presets" list if there are no presets.

[Nicklas Nordborg]

In 7870:

References #2222: Add support for manually adding any-to-any link column in table lists

Changed color of the '>' marker to a darker variant to make it match the color used for parent/child columns.