Update NV sequence diagram: Mermaid format + temp token/JWT flow

[shilpa-padgaonkar]

Problem description
The current sequence diagram for NV is provided as a static image. Additionally, it only illustrates the flow for cases where a temporary token is not used.

Expected action
Proposed improvements:

• Replace the static image with a Mermaid diagram, so the flow is easier to update and maintain in the future.

• Extend the diagram to cover scenarios where a temporary token is available, including (at minimum) the JWT Bearer token flow.

Additional context

[bigludo7]

Hello @shilpa-padgaonkar
Adding @maxl2287 (related to #207) & @fernandopradocabrillo and @AxelNennker

I'm wondering if we should not remove this schema and only indicate that the authorization flows that can be used (auth code, jwt bearer flow) is described in ICM CAMARA APIs Access and User Consent Management document. Indeed to avoid any confusion I tend to think that the schema should reflect the same mechanism and so it introduces redundancy between both.

WDYT?

[shilpa-padgaonkar]

@bigludo7 Sounds good to me.

[bigludo7]

Solved with #213