Update llama.cpp binaries to 5f631c2 and align the LlamaContext

GitHub actions

- Caching that folder, so CI only has to download it once.

- using 6.0.x instead of 7.0.x

The poc of the test is working know. Finally the problem error seems to be related with the process stopping.
Once I changed the context with today llama.cpp binaries is working OK

It solves the problem with netstandard2 (is it really netstandard2 a thing right now?)
Change context to solve problems.

5f631c2679

Fixed Mirostate Sampling

Fixed Spelling Mirostate -> Mirostat

Fixed Memory pinning in Sampling API

Low level new loading system

Fixed More Multiple Enumeration

Fixed Multiple Enumeration

LLamaContextParams epsilon and tensor split changes

- Moved repeated code to convert `LLamaTokenDataArray` into a `LLamaTokenDataArrayNative` into a helper method.
   - Modified all call sites to dispose the `MemoryHandle`
 - Saved one copy of the `List<LLamaTokenData>` into a `LLamaTokenData[]` in `LlamaModel`

- Additional comments

This change _only_ implements the low level API and makes no effort to update the LlamaSharp higher level abstraction.

It is built upon llama `b3f138d`, necessary DLLs are **not** included in this commit.

Instruct & Stateless web example implemented

Larger states

Memory Mapped LoadState/SaveState