Replace savannah bugs by corresponding JIRA tasks (@pkoppenb)

Cherry-picked from !684 (merged)

added Documentation all-slots cleanup labels

• [2020-09-05 00:11] Validation started with lhcb-run2-patches-dev4#441
• [2020-09-05 00:16] Validation started with lhcb-run2-patches#807
• [2020-09-05 00:27] Validation started with lhcb-run2-patches-py3#31
• [2020-09-06 00:10] Validation started with lhcb-run2-patches#808
• [2020-09-06 00:12] Validation started with lhcb-run2-patches-py3#32
• [2020-09-06 00:12] Validation started with lhcb-run2-patches-dev4#442
• [2020-09-07 00:12] Validation started with lhcb-run2-patches-dev4#443
• [2020-09-07 00:14] Validation started with lhcb-run2-patches-py3#33
• [2020-09-07 00:16] Validation started with lhcb-run2-patches#809
• [2020-09-08 00:09] Validation started with lhcb-run2-patches-dev4#444
• [2020-09-08 00:13] Validation started with lhcb-run2-patches-py3#34
• [2020-09-08 00:18] Validation started with lhcb-run2-patches#810

removed all-slots label

merged

mentioned in commit 0fd8898e