Add support for configurable invoice sequence scopes

[tomkalon]

Q	A
Branch?	2.2
Bug fix?	no
New feature?	yes
BC breaks?	no
Related tickets	#131
License	MIT

Introduced InvoiceSequenceScopeEnum (monthly, annually, global)
Modified SequentialInvoiceNumberGenerator to support:

• monthly invoice number resets
• annually invoice number resets
• default global sequence (current behavior)

Added ENV parameter:
SYLIUS_INVOICING_SEQUENCE_SCOPE=monthly

Accepted values:
monthly: separate invoice sequences per month
annually: separate invoice sequences per year
(anything else or empty): one global sequence

Kept backward compatibility — global behavior is preserved unless explicitly configured

[jkindly]

Overall looks OK, but I wonder if we can make it more "Admin friendly". For example:

• add select field with period in channel settings
• catch all defined periods as tagged parameters and display them in the select above
• create period resolver/generator

If someone wants to extend scope (e.g. quarterly), the only thing to do is to add new scope as parameter + it's resolver/generator.
Also, there should be split for channels, because in channel X it can be monthly, but in channel Y it can be annualy.
Extending entity and making a new migration sounds bad for adding a new period.

It's just nice to have, but I think it's easy to implement.

btw. All builds fail.