Add retry decorators

[Scandie]

Add retry decorator to methods '_get_resource_item' and
'_patch_resource_item', which will be trying to repeat
request several times in case RequestFailed exception was raised

---

This change is 

[coveralls]

Coverage increased (+0.05%) to 88.12% when pulling b72d6e8 on Scandie:a411363919429433_error_handling into 810a9c5 on openprocurement:registry.

[coveralls]

Coverage decreased (-0.1%) to 87.969% when pulling 1ad1ed2 on Scandie:a411363919429433_error_handling into 810a9c5 on openprocurement:registry.

[VDigitall]

@Scandie ще б тести.

[coveralls]

Coverage increased (+0.2%) to 88.228% when pulling c6e1b00 on Scandie:a411363919429433_error_handling into 810a9c5 on openprocurement:registry.

[coveralls]

Coverage increased (+0.2%) to 88.228% when pulling 0f53561 on Scandie:a411363919429433_error_handling into b1f651d on openprocurement:registry.

[coveralls]

Coverage increased (+0.2%) to 88.228% when pulling 1ac0e70 on Scandie:a411363919429433_error_handling into b1f651d on openprocurement:registry.