Until now, only bt5 Extension/Test/Document could be migrated from
filesystem.

From migration dialog, allow to select any Products.ERP5.Documents.* (only,
for now) to be migrated. By default, automatically select Products Documents
used by the current bt5 Portal Types (by looking at the mro() of its
erp5.portal_type classes).

XXX-BEFORE-MERGE: Add Unit Test.

In the promise file, the persistent memcached url were swapped

@georgios.dagkakis @Nicolas - moving test related things out of the erp5_corporate_identity template
test results: https://nexedi.erp5.net/test_result_module/20180419-563DDA29

/reviewed-on nexedi/erp5!645

[renderjs_ui] Move Form submission logic into one place - Page Form and add constants to Form Definition in [hal_json_style]

- allow slapos master communicator to supply software destruction
- runner reinstalls software on every commit (temporarily)
- refactor in software profile construction
- some try controls added

/reviewed-on nexedi/erp5!644

auto-generate expense sheet by using title and number

- before create a new instance checks if the current testsuite has an old one
- re-uses file-dictionary functions of frontend software checks
- minor fixes

/reviewed-on !615

Display relation field select list if focus is activated
Fixup click handling

(fix: e46ade7a)

(fix erp5.git/eb5f1fb1)

As it is a common pattern to set validators on hidden fields
to display custom errors to users.

By using `os.path.normpath` we also support paths with a trailing slash.

Also, change the JSON format and update tests according to these changes