Support sanitizing specified headers in tap filter output

[hwyuan]

Title: Support sanitizing specified headers in tap filter output

Description:
When using the Tap filter to inspect request details, it could be beneficial to be able to sanitize certain headers (e.g., auth) so that it's easier for the downstream consumers to process the tapped request details.

[optional Relevant Links:]
tap filter: https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_filters/tap_filter

[ravenblackx]

@xu1zhou