Define and use TOR_ADDRPORT_BUF_LEN

In legacy/trac#33918 (moved), we discovered a bug where IPv6 addresses were being truncated in logs.

During the fix, we noticed that we had a TOR_ADDR_BUF_LEN, but no equivalent constant for addresses and ports. The new TOR_ADDRPORT_BUF_LEN should allow space for:

• TOR_ADDR_BUF_LEN
• IPv6 brackets (2, if not included in TOR_ADDR_BUF_LEN already)
• the port separator (1)
• the port (5)

We should check for other truncation errors while making this change.