Broken links (missing files)

[donnyquixotic]

Description
Missing linked markdown and license files

• On source page path = /native/eosio_toolkit/ -> linking to ./03_before-you-begin.md (resolved as: /native/eosio_toolkit/03_before-you-begin.md)
• On source page path = /native/eosio_toolkit/contract_dev_toolkit -> linking to ./LICENSE (resolved as: /native/eosio_toolkit/LICENSE)

Once resolved, revert config onBrokenLinks param value back to 'throw' (currently set to 'warn' to prevent breaking cloudflare build, see #86 )