[FIX] orm write: do not try to store computed & stored fields for relational records deleted by *2many fields

opw-613772
[FIX] loading: always process auto-installed modules for new databases

If the server was started without -i or -u and
happened to initialize a fresh database,
auto-installed modules that depend
on `base` only would stay in status "to install"
without actually being installed (until the next
installation round was triggered).
This was of little consequence in 7.0, but causes
a crash in 8.0.

Fixes #953
[FIX] account_anglo_saxon: correctly set the accounts for returns

The generated moves on a return should be the reverse of the outgoing move.
Fixes #1817, opw 604417
[FIX] stock/purchase: dates and currency rates

Use the currency rate of the purchase date instead of the one of at the reception time (opw 610430)
[FIX] hr_timesheet_sheet: avoid error when sort attendances

When an attendance line is edited, the tuple has no key 'name' which lead to a traceback.
Fixes #546