KTXDecoder: Update and add new universal transcoders

[Popov72]

Fixes #12002

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Snapshot stored with reference name:
refs/pull/13284/merge

Test environment:
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Links to test babylon tools with this snapshot:

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[sebavan]

LGTM but I know nothing regarding this area so lets wait on @bghgary review :-)

[RaananW]

My approval - Just for the changes for the public server :-)

The rest is for @bghgary

[bghgary]

Are the new WASM files compatible with old code? Do we need to host a second version like we did for the Basis transcoders?

[Popov72]

No, the new WASM files (at least the RGBA transcoders) are not compatible with the old code. I'm going to rename them.