Add new platforms strings to PlatformInfo (@clemenci)

See merge request !3062 (merged) and !3073 (merged)

(cherry picked from commit 330dfed1 and 243086ac)

added all-slots modernisation labels

mentioned in merge request !3062 (merged)

added 1 commit

• fcdf8ec5 - Fix typo in known_platforms list (follow up !3062 (merged))

Compare with previous version

changed the description

• [2021-05-26 00:53] Validation started with lhcb-run2-gaudi-head#134
• [2021-05-26 00:57] Validation started with lhcb-run2-patches-dev4#703
• [2021-05-26 01:00] Validation started with lhcb-run2-patches#968
• [2021-05-27 00:49] Validation started with lhcb-run2-gaudi-head#135
• [2021-05-27 00:53] Validation started with lhcb-run2-patches-dev4#704
• [2021-05-27 00:57] Validation started with lhcb-run2-patches#969
• [2021-05-27 01:36] Validation started with lhcb-run2-gaudi-head#135
• [2021-05-27 01:46] Validation started with lhcb-run2-patches#969

removed all-slots label

mentioned in commit bda24094

merged

added legacy label