Initial setup to integrate Keplr with Synpress

[rabi-siddique]

The PR segregates Keplr and Metamask implementations, to allow making it easier to modify the code to ensure each module focuses on its specific tasks.

What I did:

• Created an object containing methods that involve interaction with Keplr Extension inside playwright-keplr.js. The Meta-mask-specific implementations are moved to playwright-metamask.js.
• Separate operations relevant to Keplr in keplr.js in the commands folder. In the same folder, Meta-mask-specific stuff is present in metamask.js.
• Separate plugin configs for Meta-mask and Keplr in plugins folder.
• Test cases for Keplr are placed in keplr.spec.js file. While Meta-mask-specific test cases are in metamask.spec.js.
• The differentiation between using Keplr-relevant configs and test cases is being identified through an environment variable EXTENSION that is passed through a package.json script.
• Added an implementation to download the Keplr Extension based on the provided version through an environment variable.

[frazarshad]

LGTM. we can start with this as the base and can make any refinements needed later