toaster: Change placeholder attribute in variables table

Set placeholder attribute for the search input field in
the variables table to "Search BitBake variables" as per
the design specification.

[YOCTO #5998]

Signed-off-by: Belen Barros Pena <belen.barros.pena@intel.com>
toaster: Remove commented-out code from views.py

This code in the All tasks view class needed to be removed.

[YOCTO #6010]

Signed-off-by: Belen Barros Pena <belen.barros.pena@intel.com>
toaster: Fix help text typos

Fix a couple of typos in the help text of the builds
and recipes tables.

Signed-off-by: Belen Barros Pena <belen.barros.pena@intel.com>
toaster: Small fixes in tasks UI

This commit:

* Fixes an issue with white space when showing the log
in Cached tasks (task details page)

* Formats the no results alert of the "Prebuilt task
could be based on" search in the task details page

* Brings in the task outcome help text to "Prebuilt
task could be based on" table in the task details page,
to the tasks table in the recipe details page, and to
the all tasks page

* Adds the task_color tag to the "Prebuilt task could
be based on" table in the task details page, so that
each task gets the required visual treatment based on
execution

* Makes sure performance information for not executed
tasks shows in the task details page when it exists
(empty tasks often report a short time, for example)

Signed-off-by: Belen Barros Pena <belen.barros.pena@intel.com>
toaster: format packages with size = -1

Packages that have a size of -1 are virtual packages with limited
information.  Such packages should be suppressed from the package
list page for an image.  On dependency and reverse dependency lists of
package, such packages should appear in muted rows, without links,
and with help information.

The formatting rules are encapsulated into projecttags filters when
possible to minimize tests on size==-1 in the templates.

Testing the relevant pages with an HTML5 validator found a stray end
tag in package_detail_base which has been fixed in this commit.

[YOCTO #5966]

Signed-off-by: Dave Lerner <dave.lerner@windriver.com>
Signed-off-by: Alexandru DAMIAN <alexandru.damian@intel.com>