Update Governance Processes to reflect budgets + normal proposals

The [Governance Process](https://handbook.developerdao.com/about-the-dao/governance-process) page currently does not provide detail for how to apply for budgets as a Sub-DAO, only the DDIP projects itself. Therefore, it needs to be updated to include Sub-DAO's and how they are formed.

Resources:

- [Governance section of Erik's DAO Os book](https://developerdao.gitbook.io/operating-system/)
- [P-22: Governance Structure Upgrade](https://forum.developerdao.com/t/p-22-dao-governance-structure-upgrade/2615)

Also consider migrating the Budgets/Grants category into the proposal category on the forum and using tags to distinguish between the different types of proposals.

Maybe there is also a case for adopting an explicit multi-type governance proposal system like [ENS](https://docs.ens.domains/v/governance/process#types-of-proposal) and [Gitcoin](https://manual.gitcoin.co/governance-processes/proposals).