[Enhancement] Create cache in a user directory

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### How are you using the lua-language-server?

Neovim

### Which OS are you using?

Linux

### What is the issue affecting?

Other

### Expected Behaviour

`lua-language-server` should create the cache directory on the user's home directory. On Linux this should be in `~/.cache/lua-language-server/` ideally.

### Actual Behaviour

`lua-language-server` fails to start because it attempts to create the cache directory in a system directory which a regular user doesn't have permissions to write to.

### Reproduction steps

1. Download `lua-language-server-3.9.1-linux-x64.tar.gz` and extract it to `/opt/lua-language-server/`
2. Make sure the owner of `/opt/lua-language-server/` is `root:root`.
3. Execute `/opt/lua-language-server/bin/lua-language-server --help`
4. See error: `lua-language-server: create_directories: "/opt/lua-language-server/log/cache/40815": (generic:13)Permission denied`

### Additional Notes

_No response_

### Log File

_No response_

Begin with the `/opt/lua-language-server/bin/lua-language-server --help` reproduction and trace where the `log/cache/40815` path is selected. Verify that the cache is created under `~/.cache/lua-language-server/` for a regular Linux user, then rerun the documented startup steps without permission errors.

Written by the indexing model from the issue text.