…nd custom (self-signed) RootCAs

You can now use self-signed ca-certificates when authenticating with TLS. Using the `cacerts` property of an options `tlsAuth` object, you can now indicate the CA certificate(s) that k6 will use to verify the server certificates your tests will access. CA certificates must be in `pem` format and multiple CA certificates can be included.

```javascript
export const options = {
    tlsAuth: [
        {
            cacerts: [open("cacerts.pem")],
            cert: open("cert.pem"),
            key: open("cert-key.pem"),
            password: "cert-passphrase",
            domains: ["grpcbin.test.k6.io"], // Deprecated
        },
    ],
};
```

You can also now use per-vu TLS configuration on `grpc.Client` `connect` params. Previously, `grpc.Client` `connect` made use of a shared (immutable) `tls.Config` cloned into every VU. Now, the `connect` `params` argument can contain a `tlsconfig` key that maps to the `TLSAuth` struct. This will create a per-vu TLS configuration for the `grpc.Client` allowing you to connect to multiple mTLS endpoints in a single VU. Note: the global tls.Config will remain unmodified.

```javascript
const params = {
    plaintext: false,
    tlsconfig: {
        cacerts: ["cacerts.pem"],
        cert: "cert.pem",
        key: "key.pem",
        password: "cert-passphrase",
        domains: ["grpcbin.test.notk6.io"], // Deprecated
    }
};
const hostPort = "grpcbin.test.notk6.io:9001";
const client = new grpc.Client();

client.connect(hostPort, params);
```

Added tests around tls password and encrypted certificate key

…alhostKey and localhostEncryptedKey. (Used the same approach `net/http/internal/testcert/testcert.go` uses)

Nice catch. Thank you.

Co-authored-by: Mihail Stoykov <312246+mstoykov@users.noreply.github.com>

Nice catch. Thank you.

Co-authored-by: Mihail Stoykov <312246+mstoykov@users.noreply.github.com>

Added positive and negative test cases for grpc client connect with tls parameter

Update js/modules/k6/grpc/client.go
lib/options.go should also be updated

Co-authored-by: Mihail Stoykov <312246+mstoykov@users.noreply.github.com>

…ith-rootcas' into feature/per-vu-grpc-tls-config-with-rootcas

…h-rootcas

Unsure why the test passes locally but fails in CI

Co-authored-by: Oleg Bespalov <olegbespalov@gmail.com>

Co-authored-by: Oleg Bespalov <olegbespalov@gmail.com>

Co-authored-by: Oleg Bespalov <olegbespalov@gmail.com>

Co-authored-by: Oleg Bespalov <olegbespalov@gmail.com>

Co-authored-by: Mihail Stoykov <312246+mstoykov@users.noreply.github.com>