Integrate docsite (#396)

* migrate docs to antora

* add docs bump to RELEASING

* migrate from markdown to adoc format

* update antora name

* fix index adoc format

* Apply suggestions from code review

Co-authored-by: Francisco <frangio.1@gmail.com>

* add crosslink to solidity, remove advisory

* fix extensibility

* add admonitions and scape underscores

* update navbar

* merge access control docs

* Apply suggestions from code review

Co-authored-by: Andrew Fleming <fleming.andrew@protonmail.com>

* remove unused style. try toc clause

* return toc. fix links for access

* fix access links

* fix account doc links

* fix erc20 doc links

* fix erc721 doc links

* fix extensibility doc links

* fix introspection doc links

* fix proxies doc links

* fix security doc links

* fix utils doc links

* fix links

* fix utils doc links

* fix links and references

* fix links

* inline None.

* adapt access accounts erc20 to new dir structure

* adapt erc721 to new dir structure

* adapt extensibility and introspection to new dir structure

* adapt proxies security utilities to new dir structure

* fix merge conflict

* apply review suggestions

* Update docs/modules/ROOT/pages/accounts.adoc

Co-authored-by: Andrew Fleming <fleming-andrew@protonmail.com>

* fix formatting

* escape character

* Update docs/modules/ROOT/pages/index.adoc

Co-authored-by: Francisco <frangio.1@gmail.com>

* replace links with permalinks

Co-authored-by: Francisco <frangio.1@gmail.com>
Co-authored-by: Andrew Fleming <fleming.andrew@protonmail.com>
Co-authored-by: Andrew Fleming <fleming-andrew@protonmail.com>

RELEASING.md

@@ -18,14 +18,24 @@ to
 # OpenZeppelin Contracts for Cairo v0.2.0 (account/Account.cairo)
 ```
 
-(3) Create a release branch and add a tag to it. This branch can be useful if we need to push a hot fix on top of an existing release in the case of a bug.
+(3) Update documentation version in `docs/antora.yml`
+
+```diff
+ name: cairo-contracts
+ title: Contracts for Cairo
+-version: 0.1.0
++version: 0.2.0
+ (...)
+```
+
+(4) Create a release branch and add a tag to it. This branch can be useful if we need to push a hot fix on top of an existing release in the case of a bug.
 
 ```sh
 git checkout -b release-0.2.0
 git tag v0.2.0
 ```
 
-(4) Push the tag to the main repository, [triggering the CI and release process](https://github.com/OpenZeppelin/cairo-contracts/blob/b27101eb826fae73f49751fa384c2a0ff3377af2/.github/workflows/python-app.yml#L60).
+(5) Push the tag to the main repository, [triggering the CI and release process](https://github.com/OpenZeppelin/cairo-contracts/blob/b27101eb826fae73f49751fa384c2a0ff3377af2/.github/workflows/python-app.yml#L60).
 
 ```sh
 git push origin v0.2.0