internal: port anymap
## Description
- The anymap crate has been ported. During this process, unnecessary features for rust-analyzer have been removed.
- From the tests that were checking the existing licenses, the anymap license (`BlueOak-1.0.0 OR MIT OR Apache-2.0`) has been removed.
## Requests
- While porting the code this time, I have tried to respect the original author's intentions and have kept the comments/codes as much as possible. Please don't hesitate to tell me if you think the comments/codes also need to be appropriately modified.
- If there are any necessary changes regarding the licensing or anything else, please let me know so I can fix them.
## Issue
https://github.com/rust-lang/rust-analyzer/issues/15500
Switch to in-tree rustc dependencies with a cfg flag
We can use this flag to detect and prevent breakages in rustc CI. (see #14846 and #15569)
~The `IN_RUSTC_REPOSITORY` is just a placeholder. Is there any existing cfg flag that rustc CI sets?~
Implement builtin#format_args, using rustc's format_args parser
`format_args!` now expands to `builtin#format_args(template, args...)`, the actual expansion now instead happens in lowering where we desugar this expression by using lang paths.
As a bonus, we no longer need to evaluate `format_args` as an eager macro which means less macro expansions overall -> less cache thrashing!
Fixes https://github.com/rust-lang/rust-analyzer/issues/15082
internal: Record import origins in ItemScope and PerNS
This records the import items definitions come from in the module scope (as well as what an import resolves to in an ItemScope). It does ignore glob imports as thats a lot more work for little to no gain, glob imports act as if the importing items are "inlined" into the scope which suffices for almost all use cases I believe (to my knowledge, attributes on them have little effect).
There is still a lot of work needed to make this available to the IDE layer, but this lays out the ground work for havin IDE layer support.
cc https://github.com/rust-lang/rust-analyzer/issues/14079
