telemetry(amazonq): add telemetry for code generated and code accepted

[kelvin-klchu]

Problem

• we need to define a way to measure code generated and code accepted from /dev feature

Solution

• we compute the char and line difference between the two files
• all generated codes are immediately reported in telemetry
• within the same session, de-duplication is done to avoid reporting the exact same changes twice across different code gen iterations
• currently, only accepted changes with new lines added will be reported

Special Note

charsAdded and charRemoved may be slightly different from the count you manually get from the IDE.
The reason is because new line character \n is not counted here in the computeDiff method.

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License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[kelvin-klchu]

rebase changes and resolved conflicts