Add redirections

[oxarbitrage]

I think it will be good to redirect some links that were available in the old doc site into the new versions here.

For example:

http://docs.bitshares.org/tutorials/uia-create-manual.html

Is broken, it should redirect to: https://dev.bitshares.works/en/master/bts_guide/tutorials/mpa-create-manual.html

Others are: https://dev.bitshares.works/en/master/bts_guide/tutorials/mpa-create-manual.html
and https://dev.bitshares.works/en/master/api/blockchain-objects-ids.html

Please note old links are posted in issues, forum posts, etc just as: bitshares/bitshares-core#1111 (comment)

It is important to dont lose that traffic where possible.

Thanks.

[cedar-book]

Assets relating links are here (https://dev.bitshares.works/en/master/bts_guide/tutorials/index.html#assets)

Object ID relating information is here (https://dev.bitshares.works/en/master/api/objects_ids.html#objects-and-ids)