feat: Revamp of Exit codes page

[novusnota]

Results of digging into TON Blockchain sources in search of truth & exit codes:

• TON docs do not feature a lot of existing exit codes
• Tact misattributes some of the exit codes (as of now), and generally skips a lot (as of now)

As one of the results of this PR, the number of exit codes on this page grew ~3.2 times — 15 (initial) vs. 48 (now) :)

TODO:

• [ ] Complete the descriptions of exit codes 0...14
• [ ] Augment and fix descriptions of result codes (exit codes of action phase), 32...50

Closes tact-lang/tact#887

[novusnota]

Closed in favor of opening a new PR in https://github.com/tact-lang/tact

The commits here should be kept for a while, so the branch must not be deleted!