Expose API used by h3

[birneee]

currently, the h3 implementation directly accesses internal quiche fields, functions, structs, and macros, which currently cannot be used by other protocol implementations that want to build on top of quiche, such as moq.

This is also also mentioned here: https://github.com/cloudflare/quiche/issues/2034#issue-3020045703

used by h3:

• quiche::Connection::dgram_enabled
• quiche::Connection::grease
• quiche::Connection::qlog
• quiche::qlog_with_type
• quiche::QlogInfo
• quiche::stream::is_bidi
• quiche::stream::is_local
• quiche::stream::StreamMap::is_collected
• quiche::stream::StreamMap::max_streams_bidi

used by h3 tests:

• quiche::Connection::undecryptable_pkts
• quiche::Connection.tx_cap
• quiche::frame::Frame
• quiche::range_buf::RangeBuf
• quiche::stream::StreamMap::blocked