remote api functions: Roundcube plugins functions

Adds a function set to remote api for 'Roundcube plugins functions' that includes only the functions the roundcube plugins actually use.

This both simplifies the configuration for roundcube and increases server security (allowing the full set of (38) functions included in 'Server functions' and 'Client functions' makes me cringe, when only 3 are actually used).

changed milestone to %3.2.2

added API label

changed the description

changed milestone to %3.2.3

added MR: Review Pending label

removed API label

added API label

added MR: Reviewed TP label

approved this merge request

removed API label

added API MR: Reviewed MB labels

removed API label

merged

mentioned in commit 013955a8

removed MR: Review Pending label