Previously, when using the native schema, invoice expiries were incorrectly
stored as 64-bit values (expiry in nanoseconds instead of seconds), causing
overflow issues. Since we cannot determine the original values, we will set
the expiries for existing invoices to 1 hour with this migration.
Previously paginated queries offseted the add_index_get, add_index_let,
settle_index_get and settle_index_let parameters with the paginators
current page offset, however this was incorrect as we can just use
SQL's LIMIT/OFFSET to paginate. This commit fixes this issue and adds an
optional parameter to the constructor of the invoice SQL store to set
page size. This is useful when testing as we can now cover pagination
correctly with our existing unit tests.
Previously if the `reverse` named arg was unset (value of NULL), then
SQL would order by NULL instead of ID causing undifined ordering of the
returned rows. To fix that we check for NULL and also make sure to set
the `reverse` arg in the code explicitly as it in the generated code it
is an `interface{}` instead of `bool`.
For SQL transactions, we often accumulate results in variables declared
outside the closure's scope. To eliminate the need for manually clearing
these containers, we introduce a reset function to ExecTx, mirroring the
approach already adopted in kvdb.
