Consider merging all packages into fuels

[arboleya]

The idea is to experiment with merging all packages/* into packages/fuels.

A single package should simplify the repo maintenance, build times, and feedback loop.

Also, it should make it easier to make our library fully tree-shakable and avoid bloating the final build.

• Consider moving account test utilities around #1751
• Consider moving Contract package into Program #2475
• Consider moving Address package into Account #2476
• Consider moving Hasher package into Crypto #2477
• Consider moving script package into program #2478

[arboleya]

Other points of interest:

• Review tsup dependency and configs
• Review utility of integrating with tsc project references (docs)

[petertonysmith94]

We can conclude the following discussion if we go with this approach:

• Restructuring Packages & Directories #1517

[maschad]

Should we also consider merging abi-coder into abi-typegen as well?

[arboleya]

Closing EPIC — sub-issues will be resolved individually.