Implement Events importer for VK

[RegiKein]

Implement Events importer for VK

Acceptance criteria

1. Implement VkRepostEventsAnalyzer 1.IsEvent - method which should check:
   1. if the post is reposted from another event - it should be identified like Event
   2. if the post is reposted from another group - it should be skipped
      2. Analyze has an argument VkPost
2. Implement VkEventsImporter
   1. Import method returns PublicEvent object with fields:
      1. DateTime of start
      2. DateTime of end
      3. Title
      4. Attachments
      5. URL link to this event at vk.com
3. Unit tests should be written

Technical details

classDiagram

class IVkApiClient{
    <<interface>>
    +GetGroupInfoAsync(groupId, cancellationToken) Task~VkGroupInfo~
    +GetPostsAsync(request, cancellationToken) Task~VkPost[]~
}
class VkApiClient
IVkApiClient <|.. VkApiClient

class PublicEvent
class IVkEventsImporter{
    <<interface>>
    +ImportAsync(vkGroupId, cancellationToken) Task~PublicEvent~
}

class VkRepostEventsAnalyzer{
    +AnalyzeAsync(VkPost) Task~VkPost~
}
class VkEventsImporter
class VkPost
VkEventsImporter ..> IVkApiClient
VkEventsImporter ..|> IVkEventsImporter
PublicEvent <.. IVkEventsImporter
VkRepostEventsAnalyzer ..> VkPost
IVkApiClient ..> VkPost

VK API