docs: browser session management

docs/setup/using_in_browser.md

@@ -0,0 +1,11 @@
+[Initialization of library](./intialization.md) requires several properties of [signer](../api/classes/modules_signer.SignerService.md):
+
+- The signer meets [EIP-191: Signed Data Standard](https://eips.ethereum.org/EIPS/eip-191)
+- Public key. This is legacy parameter, which was used to initialized DID document
+
+These properties are not directly exposed by all signers, such as Metamask, and thus are determined in runtime by sending test sign request.
+In order to improve user expirience when library is used in browser it tries to get these parameters from local storage.
+In order to implement application specific session management the library doesn't modify storage and relies on the application to set `isEthSigner` and `PublicKey` local storage variables on login.
+For example to disable session application will not set properties.
+If properties are not in local storage then signer initialization will be completed on login to ssi-hub.
+Initialization is postponed in order to prevent double signing when user is not logged in ssi-hub.

mkdocs.yml

@@ -6,6 +6,7 @@ nav:
   - Setup:
       - Initialization: setup/initialization.md
       - Logging: setup/logging.md
+      - Using in browser: setup/using_in_browser.md
   - Guides:
       - Application: guides/application.md
       - Asset: guides/asset.md