Docker v0.15.5-dev2

What's Changed

• change nonce init to respect xt in tx pool by @brenzi in #1648
• charge byte fees for notes by @brenzi in #1649
• session-proxy for delegate signing and key storage by @brenzi in #1655
• remove vulnerable rpc by @brenzi in #1658
• [ci] bump artifact actions to v4 by @clangenb in #1660
• remove EPID call for mrenclave of self by @brenzi in #1662

Full Changelog: v0.15.3...v0.15.5-dev2