While !login is called, the panel is rendered before the n.me is modified, so the link for "Account" on the panel is wrong until the user refresh the site after login.

To allow promises to update thier sys.path and import needed dependencies,
module load is now moved to PromiseProcess class. This prevent promises to modify
sys.path of parent process.

Remove Search Bar (not required as the user can use the module)
Fix sort on the listboxes
Include a Buttom Bar to include some shortcurts for manage tickets
Only show Pending tickets on the frontpage.
Show Modification Date on the Tickets listbox.

This will allow the user use this dedicated feed for build some push notification or something similar.

Some context: I'm trying to build Go 1.10 under slapos and get failures
like:

	ok   os      0.782s
	PASS
	testing: can't write /tmp/go-build511454695/b682/testlog.txt: write /tmp/go-build511454695/b682/testlog.txt: broken pipe
	FAIL os/exec 0.947s
	...
	ok   cmd/vet/internal/cfg    0.002s
	2018/04/03 18:13:29 Failed: exit status 1
	golang1.10: Command failed with exit code 1:   cd src && ls -l /proc/self/fd && ./all.bash && cp -alf .. /srv/slapgrid/slappart5/srv/runner/software/099a7368550e95d120639cb03b6d47c8/parts/golang1.10
	golang1.10: Compilation error. The package is left as is at /srv/slapgrid/slappart5/srv/runner/software/099a7368550e95d120639cb03b6d47c8/parts/golang1.10__compile__/go where you can inspect what went wrong
	While:
	  Installing golang1.10.
	Error: System error

This was traced to https://github.com/golang/go/issues/24285, which in turn was
traced by me to the fact that golang os/exec tests close all file descriptors >
4 assuming that only stdin, stdout, stderr, epoll and testlog file descriptors
are there:

	https://github.com/golang/go/blob/26e0e8a840/src/os/exec/exec_test.go#L402
	https://github.com/golang/go/blob/26e0e8a840/src/os/exec/exec_test.go#L415

However when go build is run under slapos it starts with the following
descriptors inherited in the environment:

	lr-x------ 1 slapuser5 slapuser5 64 Apr  3 17:57 0 -> pipe:[2969903608]
	l-wx------ 1 slapuser5 slapuser5 64 Apr  3 17:57 1 -> pipe:[2969903609]
	l-wx------ 1 slapuser5 slapuser5 64 Apr  3 17:57 2 -> pipe:[2969903609]
	l-wx------ 1 slapuser5 slapuser5 64 Apr  3 17:57 3 -> /srv/slapgrid/slappart5/srv/runner/software.log

i.e. the file descriptor for software.log (under `slapos node software`) is
passed opened to spawned buildout commands -> and oops - go build failure.

I'm not saying go behaviour is correct. However for slapos it is also not good
to leak e.g. log file descriptors to spawned processes (e.g. what if spawned
child writes there by mistake?).

Since fixing on Go side is not very easy, because it will probably require
non-small testing infrastructure refactoring, I decided to fix on SlapOS side,
because it is a) easier, and b) correct & good to do in any way.

----

To fix we just pass close_fds=True to subprocess.Popen run from under
SlapPopen, which means that popen will close all file descriptors besides
stdin, stdout & stderr for child. close_fds default is already True for python3

	https://www.python.org/dev/peps/pep-0433/#subprocess-close

for the reason that it is frequent mistake for programmers to not leak file
descriptors to spawned processes.

However on python2, which we are still using, close_fds default is False.

So let's fix the default on our side.

/reviewed-by @jerome, @rafael
/reviewed-on nexedi/slapos.core!42

Hiding such environment variable prevent easy access to the user
owning the software or the user owning the instance.

Some instances needs to have the actual username of the instance in their
config files and some softwares needs access to the username of user
building the software. This is - in theory - easy to do in zc.buildout
thanks to https://collective.github.io/collective.recipe.grp/ , but the
way slapos run buildout with some environment variables hidden made it
not possible.

Fixes [#20180402-716ACB](https://nexedi.erp5.net/bug_module/20180402-716ACB/)

/reviewed-on !41