Create Guides Section

to do:
- [ ] create Guides section
- [ ] move all guides under Builder section into Guides section(step-by-steps, walkthroughs, guides)
- [ ] flatten current Guides structure (minting doesn't need a sub-section)
- add an overview for each section in builder
  - [ ] Contracts
  - [ ] Wallet
  - [ ] Gas Tank
  - [ ] Node Gateway
  - [ ] Marketplaces
  - [ ] Indexer
  - [ ] Settings and Collaborators