- Modified `GetEmbeddings` method to be async

Removed `SafeLLamaHandleBase` Constructor

- Also fixed `ToString()` in `SafeLLamaHandleBase`

This results in windows users not needing to rename the DLL. This allows native llama builds to be dropped in, even on windows.

I also took the time to update the documentation, removing references to renaming the files, since the names now match.

Fixes #463

Bumps [System.Text.Json](https://github.com/dotnet/runtime) from 8.0.0 to 8.0.1.
- [Release notes](https://github.com/dotnet/runtime/releases)
- [Commits](https://github.com/dotnet/runtime/compare/v8.0.0...v8.0.1)

---
updated-dependencies:
- dependency-name: System.Text.Json
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Swapped `StatelessExecutor` to use `llama_decode`!

- Growing more than double, if necessary

- Added `logits_i` argument to `Context.ApplyPenalty`
 - Added a new exception type for `llama_decode` return code

- using less `NativeHandle`
 - Using `StreamingTokenDecoder` instead of obsolete detokenize method

- Added a `DecodeAsync` overload which runs the work in a task
 - Replaced some `NativeHandle` usage in `BatchedDecoding` with higher level equivalents.
 - Made the `LLamaBatch` grow when token capacity is exceeded, removing the need to manage token capacity externally.

Model Metadata Loading Cleanup

- Clarified comments on native metadata loading methods

- Checking if model is readable

Added a check for EOS token in LLamaStatelessExecutor

- Properly displaying `LLamaToken`
 - Removed all tokenisation code in `SafeLLamaContextHandle` - just pass it all through to the `SafeLlamaModelHandle`
 - Improved `SafeLlamaModelHandle` tokenisation:
   - Renting an array, for one less allocation
   - Not using `&tokens[0]` to take a pointer to an array, this is redundant and doesn't work on empty arrays

LLamaToken Struct

Safer Handle Initialisation

- made `llama_backend_init` private. This is automatically called, there is no way it can correctly be used externally.
 - made `llama_token_to_piece` safe (Span instead of pointer)

- Wrapped some native functions which take (pointer, length) in function which take a `span` instead.

- Made `NativeApi` into a `static class` (it's not intended to be instantiated)
 - Moved `LLamaTokenType` enum out into a separate file
 - Made `LLamaSeqId` and `LLamaPos` into `record struct`, convenient to have equality etc

bump sk to 1.0.1 & km to 0.18