feat(ts): use native fetch instead of axios

[TartanLeGrand]

With Node 18 having native support for the fetch API, there is no need anymore to have a separate library for network communication.

This PR switches the typescript-axios generator out against the typescript-fetch one. If backward compatibility for older node versions is still wanted, this could instead be released as a separate package (@ory/client-fetch).

This would hugely benefit frontend projects, as users would have to download one dependency less, thus reducing loading times.

BREAKING CHANGES: This patch requires a fetch polyfill on NodeJS versions 16 and lower.

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Further comments

#256

[aeneasr]

#341 :)