Support predicated reading/copying

[fzhinkin]

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In some cases, it might be helpful to read from a source while a predicate is true instead of reading some fixed number of bytes.

One example is reading a line (Source.readLine/Source.readLineStrict) where the predicate is implicit. Another example of similar idea is Source.readWithSeparatorTo from dataforge-core project (https://github.com/SciProgCentre/dataforge-core/blob/a136db16ff9fb0de938d124ac0fe9f3408ccc030/dataforge-io/src/commonMain/kotlin/space/kscience/dataforge/io/ioMisc.kt#L121) where data from a source is copied into a sink until some multi-byte separator appears.

It seems worth supporting the reading with a predicate.