See merge request nexedi/slapos.core!301

Since during maintenance of Hosting Subscription it's possible to end up with
many root Software Instances (of which many might be destroy_requested) it's
needed to support such situation while creating upgrade decision and finding
upgradeable Software Release.

   Contributed by Romain

- more reliable crontab parsing
- execute command the same way as dcron
- fix poor escaping when execute command

  Usage of raise it don't lead to inconsistency
  Since we can merge aggregated Packing Lists, now we consider the sum() rather the invidual comparation.

  Contributed by Romain.

    Invoice Number is added to make easier to user track which invoice is which.

See merge request nexedi/slapos.core!294

   Include wider coverage on the security tests related to the "Share" feature,
   implemented via Tracking API.

See merge request nexedi/slapos.core!288

For technical reasons the ? for Software Release allows simple hacky multiple
software releases to be created, which share exactly the same profile code,
and so JSON Schemas. So for such, use original Software Release JSON Schemas.

This commit introduces the `local_software_release_root` parameter.
This parameter is then forwarded as the SR root path for slapproxy.
By default the value is `/`, the same as the default in slapproxy.

The 'local_software_release_root' parameter can be set in slapos.cfg:
    [slapproxy]
    local_software_release_root = <path>
or via the command line using:
    slapos proxy start --local-software-release-root <path>

When slapproxy starts, it updates all local URLs that are subpaths of
the previous root path to be subpaths of the new root path instead:
    <previous-root-path>/<subpath>   =>   <new-root-path>/<subpath>

The default root path is '/'. This means that by default slapproxy
behaves the same as before.

Include 'forwarded_partition_request' table in the tables to be
migrated when the database is upgraded, starting with version 11.

By default standalone will use the `slapos` executable in PATH.
This option allows a specific slapos binary to be used instead.