Combine all Lockups into a singleton contract

[smol-ninja]

^{Originally discussed in #1064}

The task is to write a singleton contract that can represent all lockup streams and see if its viable.

[smol-ninja]

Question to @sablier-labs/solidity:

Should be have separate MAX_COUNT for segments and tranches (status quo); or should we use the same value for both?

If you look at their values, they are very close to each other. Therefore, my recommendation is to use the same value for both. The common MAX_COUNT would be defined as the maximum value that does not let either of the two exceeds the block gas limit.

[PaulRBerg]

Makes sense to use the same value.

[andreivladbrg]

i also agree that the same value for both is better

[smol-ninja]

Test deployment of Lockup contract:

1. Lockup deployment
2. VestingMath library
3. Helpers library

Remarks:

• Foundry automatically deploys and links libraries without have to explicitly specify them. Warp output.
• Etherscan verification requires --libraries arguments (foundry book). Warp output.
• Once verified, Etherscan shows the library code on the contract page.

[smol-ninja]

Also, I don't know the answer but the createWithDuration on the singleton contract is cheaper than deployed Lockup Linear contract (keeping all parameters same).

1. 174,000 on singleton
2. 205,120 on deployed LockupLinear

Seems like calls to public libraries ain’t affecting the gas usage.