if we have host2 inside host1 inside host0 then routing from host0 to host2 needs to specify 'via' address because the destination address (of host2) is not directly seen through slaptap of host0 (because it goes only to host1).

this commit introduces a new constraint: users must now put the IPv6 address `network::1` on their ethernet interface inside the VM.

/cc @jm @rafael @alain.takoudjou

/reviewed-on nexedi/slapos.core!102

Once a user pays for a reservation, the ERP5 can generate a deduction (complete or partial). The code here, includes the needed simulation code for expand and merge the Deduction into the invoice.

Use cache to  save some promise instance information.
First run of slapgrid fill each promise cached (when there is no cache). The next run will check some usefull info like if promise `is test less` or promise `is anomaly less` directly from cache without need to import the module.

Cache is updated if promise file or module change, or if the promise periodicity expire (when the promise it update cache).

/reviewed-on nexedi/slapos.core!101

- Round tax comparation, else we hit floating point impression.
- Free trial user is defined by ERP5 Login reference and not Person Reference.

Simple subscription Case
Request three instances (ie.: 3 VMs) Case
Two concurrent Subscriptions Case

If the first 3 months are payed, the subscription request is confirmed (allowing allocation).

When causality is set and it is a Subscription Request, do not aggregate services (it will generate individual inviduals invoices per Subscription).

When a user has multiple requests, it should not merge, and it should generate 1 invoice per subscription request.

slapos_accounting: Use specific trade condition if Hosting Subscription comes from a Subscription Request

This allow the system differ the 2 scenarios.

When the Hosting Subscription comes from a Subscription Request, the Trade Condition applied is a different one (slapos_aggregated_subscription_trade_condition).

Update all related scripts to work accordinally.

SPL on this case are started as soon they are created and a payment generated.

This is used for subscription mode, like rapid.space VM-Like services.

Subscription and Trial uses setDefaultEmailText when create a Trial/Subscription as annonymous which will trigger this workflow and raise Unauthorized when invoke Coordinate_beforeCoordinateTextChange.

As Reacheability/Unreacheability is not tracked on SlapOS master for now, so this commits remove the interaction workflow for Email (only).

Code migrated from testSlapOSERP5DefaultScenario.

This would guarantee that the ungenerated payment from others tests are generated, while you are running live tests.

/reviewed-on nexedi/slapos.core!99

This fixes a regression introduced in commit 7467ef4c
("Add Python 3 support").

/reviewed-on nexedi/slapos.core!98

The reload part is mainly used for tests, module is reloaded if the promise file has changed. Here, __file__ ends with pyc when promise_path ends with py.