[release-1.20] Blog post for egress SNI routing. (#14211)

* Added draft blog post for egress SNI routing.

* new note and fix text block

* shrink figure

* linter fixes

* style figure and back to wikipedia as an example

* Added testing instructions.

* combine two VSs into one

* some wording fixes for egress-sni blogpost

* adding suggested changes

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* adding suggested changes 2

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* linter fix

* Apply suggestions from code review 3

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* Apply suggestions from code review 4

Co-authored-by: Michael <haifeng.yao@daocloud.io>
Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* "last" updates to egress SNI post

* Update content/en/blog/2023/egress-sni/index.md

Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>

* update image for egress sni blog post

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Co-authored-by: Gergo Huszty <gergo.huszty@ibm.com>
Co-authored-by: Gergo Huszty <gergo.huszty@digitaltrip.hu>
Co-authored-by: Frank Budinsky <frankb@ca.ibm.com>
Co-authored-by: Michael <haifeng.yao@daocloud.io>