Bug 30984: (QA follow-up) Switch from mediumtext to varchar(255)

Bug 30984: (QA follow-up) Switch from mediumtext to varchar(255)

My research indeicates that tinytext of less than 40 bytes uses
about the same storage as a varchar(255). Also, using
a TEXT field in a complex query may create a temp table.
varchar fields are also more efficient for sorting on.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 526606901626082831ab501609cf05e360551ce1)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 6106f6926ab64647f0e92c8f12fedb5da3e216f0)
Signed-off-by: Arthur Suzuki <arthur.suzuki@biblibre.com>