Upgrade all SDKs to the final, stable testnet release

[Shaptic]

For this task, we have the following release train :steam_locomotive::

• [x] Merge the two SDKs (done in v11.0.0-beta.5)
• [x] Release the last testnet SDK betas
• [x] Merge the stable XDR into soroban-client (ready: https://github.com/stellar/js-soroban-client/pull/167 et al.)
• [x] Merge in stable stellar-base: https://github.com/stellar/js-stellar-base/pull/710
• [x] Release @stellar/stellar-base @ v10.0.0
• [x] Upgrade everything to target the new base:
  • [x] stellar-sdk
  • [x] soroban-client
• [x] Release the stable @stellar/stellar-sdk @ v11.0.0
  • Reminder: minify the SDK bundle!
• [x] Release the stable soroban-client @ v1.0.0 (ready: https://github.com/stellar/js-soroban-client/pull/169)
  • Reminder: add a deprecation warning!