Add a Mock Layer8

[stravid87]

Description
The Layer8 Interceptor has become a performance bottleneck such that testing other optimizations is difficult because of it's operation. The purpose of this issue is to create a mock for layer8 that can still access the functionality of statsAPI but without the E2E encryption that it provides.

Acceptance Criteria

1. An mock NPM module that takes the place of the Layer8_interceptor and Layer8_middlware so that, once reintroduced, the real Interceptor and Middleware can be easily slotted back in.
2. The mock should expose all the same functionality as Layer8 currently:

export interface Layer8 {
    testWASM(arg: any): Promise<any>,
    persistenceCheck(): Promise<any>,
    initEncryptedTunnel(config: Layer8Config): Promise<boolean>,
    static(url: string): Promise<string>,
    fetch(input: RequestInfo | URL, init?: RequestInit | undefined): Promise<Response>
}

[stravid87]

UPDATE
only functions necessary Init, fetch (test, persistence & static unnecessary)

[marclupanc]

Implemented in #524