Move Pendulum ephemeral funding logic to backend

[TorstenStueber]

The funding account for the Pendulum ephemeral account is currently managed in the frontend. In order to avoid exploits:

• move this logic to the backend
• remove the hard coded secret from the codebase
• set it up to be provided as an environmental variable (e.g., PENDULUM_FUNDING_SEED)

Furthermore, the current funding account should be completely replaced with a new funding account, i.e., all tokens should be moved over to the new account.

Update

The new funding account is 6bmj4x2SZNfJUbxAjwS8M8KjMEEMfQnW6CiaEnDnyGCDpWdR.

[TorstenStueber]

Hey team! Please add your planning poker estimate with Zenhub @b-yap @bogdanS98 @ebma @gianfra-t

[prayagd]

@TorstenStueber is this a requirement for the dump txn ticket or the continuable flow ticket?

[TorstenStueber]

No, it is another security measure, but quite important.