Migrate to Eslint 9

[jahow]

Fixes #124

Also improves linting of the file extensions in import paths

[jahow]

@kensongzhu what do you think about this approach? we're staying with a very simple eslint configuration (honestly I don't want to sink too much time working with it, it's such a beast...).

[kensongzhu]

Sorry 4 late reply, be a bit busy these days, I will try to take a look at it in details on Saturday this week:) I had also a branch that migrated from eslint 9x, where I did a bit more that branch to improve typescript, feel free to take a look

https://github.com/kensongzhu/ogc-client/tree/refactor/eslint-9x

[kensongzhu]

@jahow Your config is alright, want to link the whole the project instead of just src folder, therefore made a stacked PR here, just some tiny fix on those lint errors only, feel free to checkout

[jahow]

Thank you for your feedback @kensongzhu! I'll wait for #129 to be merged and then will rebase this PR before merging.

Then we're good to make a new release :)