chore: Improve compression option (#2637)

* chore: Add Default to enum buffer::Compression

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(http sink): Remove Option on compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(kafka sink): Remove Option on compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(elasticsearch sink): Remove Option on compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(clickhouse sink): Remove Option on compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(splunk_hec sink): Remove Option on compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* docs(splunk_hec sink): Add compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(aws_s3 sink): Remove duplicated Compression enum

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(humio_logs sink): Add compression option

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore(new_relic_logs sink): Add compression field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* docs(kafka sink): Move links

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* docs: Move compression options to partial field

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore: Add fn content_encoding to buffer::Compression

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore: sink::util::Buffer require enum instead bool

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>

* chore: util::Compression impl fn extension

Signed-off-by: Kirill Fomichev <fanatid@ya.ru>