[SecurityBundle] added acl:set command
feature #9990 [SecurityBundle] added acl:set command (dunglas)

This PR was merged into the 2.6-dev branch.

Discussion
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[SecurityBundle] added acl:set command

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        | n/a

This new command allows to set ACL directly from the command line. This useful to quickly set up an environment and for debugging / maintenance purpose.

This PR also includes a functional test system for the ACL component. As an example, it is used to test the `acl:set` command.
The provided entity class is not mandatory (tests will still be green without it) but can be useful to test other ACL related things. I can remove it if necessary.

The instantiation of the `MaskBuilder` object is done in a separate method to be easily overridable to use a custom one (e.g. the SonataAdmin one).

Commits
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a702124 [SecurityBundle] added acl:set command