roadmap page filter for certain projects

[falkb]

Currently, projects are sorted in boxes, and all projects are shown. Having a multi-project environment people are often interested in just a few of it, mainly the ones they are working on. So we need a multi-choice selection box for the given projects.

[falkb]

(In [11634]) Refs #10073, #10074, #10075:

• timeline web page provides multi choice box for filtering by project
• roadmap web page provides multi choice box for filtering by project
• new ticket creation filters the milestone combobox by set project (requires custom ticket field 'project' (type=text) in trac.ini

[falkb]

(In [11673]) bugfixes:

• fixed two JS errors about undefined var options and undefined newOptions (Refs #10074)
• renaming projects must also rename the 'project' entries in db table ticket_custom (Refs #10075)

[Adrian Fritz]

Reported specific ticket (#10112) for unicode error, because and maybe it´s a wider issue (not only related to roadmap/milestone).

[falkb]

(In [11688]) Refs #10074, Refs #10076: multi-choice box height adapts to the number of projects, max. visible entries = 15

[falkb]

(In [11690]) Refs #10074, Refs #10076: hide scrollbar of multi-selection box if not necessary

[falkb]

[11710] fixes a bug where project names with umlauts were not properly handled on storing the list of selected filter-box entries to session_attributes db-table.

Previosly, a string "testä" was handled as ascii sequence u'test\xC3\xA4', and we stored one ascii sequence containing a whole list of such project names. Now the string list is stored as one unicode string separating the single strings with an artificial separator sequence of 3 slashes, which is unlikely part of a project name. This is somehow hackish, probably one day we'll come up with a nicer solution.

[falkb]

(In [11712]) Refs #10074 (addon to [11710]): bugfix for AttributeError: 'NoneType' object has no attribute 'split', seen as not logged in