feat: add FormatConfig for GenericFormat with leap second validation

[algebraic-dev]

This PR introduces a structure called FormatConfig, which provides additional configuration options for GenericFormat, such as whether leap seconds should be allowed during parsing. By default, this option is set to false.

This PR also fixes certain flaws to make the implementation less permissive by:

• Disallowing the final leap second, such as 2016-12-31T23:59:60Z, when allowLeapSeconds = false.
• Disallowing invalid leap seconds, such as 2017-06-30T23:59:60Z, when allowLeapSeconds = false.
• Disallowing leap-minute time zones, such as 2016-12-31T00:00:00+2360, and out-of-range time zones, such as 2016-12-31T00:00:00+2490.

These changes ensure that Lean aligns with TypeScript's behavior, as outlined in this table: cedar-policy/cedar-spec#519 (comment).

[leanprover-community-bot]

Mathlib CI status (docs):

• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 720f6fca94e24f21ba84805917edacef1bac9349 --onto a97813e11f962bc422a03c30b7e29dd2eefb92c8. You can force Mathlib CI using the force-mathlib-ci label. (2025-03-20 02:37:28)
• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 9466c5db25fe9e44199d2a9e837ab461716c89ec --onto 1465c23e12f6f8b608ef944be4559b1b5e38f40a. You can force Mathlib CI using the force-mathlib-ci label. (2025-03-26 21:40:43)

[TwoFX]

Please add tests for the things you fixed and in particular for the new syntax.