Docs: create a thorough page on value / transaction flow in TON Blockchain with respect to Tact

[novusnota]

It's either a re-write of https://docs.tact-lang.org/book/lifecycle/ or a standalone page. Or two: the brief one and the detailed one. Plus extensions to other pages in Communication sub-section of the Book.

The things to discuss:

1. How the contract balance gets changed and calculated
2. How the funds of internal messages (their "values") are spent
3. How external messages are processed
4. Who pays for the storage fees
5. How the raw_reserve works and best practices around it in Tact, including usage of self.storageReserve
6. How the bounced messages influence raw_reserve

In general, all things describing value / message / transaction flow. Perhaps, with diagrams. Perhaps, with interactive elements, see https://github.com/mattjennings/astro-live-code.

Related to and depends on #1073.

Links:

• https://docs.ton.org/v3/documentation/smart-contracts/message-management/message-modes-cookbook
• https://github.com/mattjennings/astro-live-code