[explorer] Enables Switching Across Networks (MystenLabs#1986)

* creates simple context switcher

* refactor and change where network printed on home page

* WIP - feed network variable to the JsonRpcProvider

* switches to Network enum that affects API calls across codebase

* stylize network switcher

* creates modal effect

* further changes to modal css

* changes to buttons for each network

* handles static env case

* can specify custom RPC URL

* smaller sidebar and buttons

* update home and error page tests

* updates tests to work

* WIP - test refactoring

* lint tidy-up

* adds licenses

* refactors tests including removing all 'any' types

* should be keys not values

* removes legacy ace comments

* improves modal display on results pages

* re-enables clicking longtext to go between object and parent address

* restore top-left home page button css

* yarn start:local starts at local

* improves rpcSetting comments

* network stored in browser

* network put into local storage and held for 3 hours

* restore start:local mode

* minor adjustments and README update

explorer/client/README.md

@@ -33,32 +33,46 @@ Before running any of the following scripts `yarn` must run in order to install
 
 # How to Switch Environment
 
-## Connecting to Remote Gateway server(e.g., DevNet)
+## Connecting to the DevNet Remote Gateway Server
 
-The Sui Explorer frontend will use the DevNet Gateway server by default: https://explorer.devnet.sui.io
+The Sui Explorer frontend will use the DevNet Gateway server by default: https://gateway.devnet.sui.io:443
 
 ```bash
 yarn start
 
 ```
 
-## Connecting to local RPC server
+## Connecting to a Local RPC Server
 
-Refer to [Local RPC Server & JSON-RPC API Quick Start](../../doc/src/build/json-rpc.md) on setting up a local RPC Server
+Refer to [Local RPC Server & JSON-RPC API Quick Start](../../doc/src/build/json-rpc.md) on setting up a Local RPC Server. If we wish to locally run the website using a Local RPC Server, then run the following:
 
 ```bash
 yarn start:local
 
 ```
 
-## Connecting to static data
+Alternatively, having run `yarn start`, click the green button at the top of the page and select the option 'Local'.
 
-The Sui Explorer can also connect to a local, static JSON dataset that can be found at `./src/utils/static/mock_data.json`.
+## Connecting to a Custom RPC URL
+
+First run the following:
+
+```bash
+yarn start
+
+```
+
+Then, click the green button at the top and select the option 'Custom RPC URL'. Type the Custom RPC URL into the input box that emerges.
+
+## Connecting to the Static Data
+
+The Sui Explorer can also connect to a local, static JSON dataset that can be found at `./src/utils/static/mock_data.json` and `./src/utils/static/owned_object.json`.
 
 For example, suppose we wish to locally run the website using the static JSON dataset and not the API, then we could run the following:
 
 ```bash
 yarn start:static
+
 ```
 
 # Other Yarn commands