Support custom TypeScript configuration

[sodic]

Update 22.08.2024

This issue should solve itself automatically after we close these two:

• Explicitly type-check user code during wasp compile #1718
• Always use the user's tsconfig.json when processing their code #2247

Original issue

The tsconfig.json files in user source only have effect on IDE support. Our users have no way of configuring the TypeScript compiler, neither for the server nor for the client.

They even get different errors in the IDE than in the terminal, which is very confusing.

We should allow them to specify desired flags in their tsconfig.json files and merge it with our tsconfig.json files (i.e., the ones we actually use when compiling).

[Martinsos]

Possibly somewhat related to #734

[sodic]

Wasp 0.12.0 shifted the goals for this issue (i.e., we no longer have different files for configuring TS on client and server), but the rest is still relevant.

Related: #1827