v2.0.0-alpha.51

Break down the components of Toit memory use when out of memory.
Support multiple providers for the same service.
Fix new lines in LSP server diagnostics.
Fix bug in i2c read.
Deprecate at and xmodem_1k libraries.
Use /etc/resolv.conf to find name servers on POSIX systems.
Add Task.group for coordinating work between multiple tasks.
Add encoding.url.QueryString.
Add option to do a GC before returning process stats.