info command: Show ContentLength instead of calculated size

info: add bitrate

Currently, the Quality is not enough to differentiate some files. For example
with this link:

https://www.youtube.com/watch?v=wHvgUD5uKPk

Among others you get these:

+------+---------+--------------------------------------------+
| ITAG | QUALITY |                  MIMETYPE                  |
+------+---------+--------------------------------------------+
|  249 | tiny    | audio/webm; codecs="opus"                  |
|  250 | tiny    | audio/webm; codecs="opus"                  |
|  251 | tiny    | audio/webm; codecs="opus"                  |
+------+---------+--------------------------------------------+

These appear exactly the same. After this change, will look like this:

+------+---------+---------+--------------------------------------------+
| ITAG | QUALITY | BITRATE |                  MIMETYPE                  |
+------+---------+---------+--------------------------------------------+
|  249 | tiny    |   56255 | audio/webm; codecs="opus"                  |
|  250 | tiny    |   75972 | audio/webm; codecs="opus"                  |
|  251 | tiny    |  149560 | audio/webm; codecs="opus"                  |
+------+---------+---------+--------------------------------------------+

Build without cgo

Build statically and add build information

Clean up dependencies

fix cipher parser 20200823

fix go mod semantic versioning

Merge pull request kkdai#97 from Julian-Chu/master

add Formats and AdaptiveFormats to Video

Add GoReleaser

Merge pull request kkdai#81 from Julian-Chu/add-error-check-to-decipher

Add error check to decipher