Add cookbook about meta on build (#1978)

* Add stub file for contract-build-meta.mdx

* Add contract-build-meta to routes

Author: elizabethengelman

docs/tools/cli/cookbook/contract-build-meta.mdx

@@ -0,0 +1,7 @@
+---
+title: Add meta data to contract WASM on build
+hide_table_of_contents: true
+description: Include meta data in the contract WASM byte code on build
+---
+
+Stub file: the real file is generated in build time by `yarn stellar-cli:build`.

routes.txt

@@ -538,6 +538,7 @@
 /docs/tools/cli
 /docs/tools/cli/cookbook
 /docs/tools/cli/cookbook/asset-management
+/docs/tools/cli/cookbook/contract-build-meta
 /docs/tools/cli/cookbook/contract-lifecycle
 /docs/tools/cli/cookbook/deploy-contract
 /docs/tools/cli/cookbook/deploy-stellar-asset-contract