Add other Components creation and properties methods (#65)

[spslater]

Changes for issue #65:

• Add methods to create, add, and get Todo, Journal, Timezone, and Free/Busy components to a calendar and moved the Alarm methods to live under the VAlarm struct.
• Todo and Journal have setters for the properties listed in RFC5545 and RFC7968
• Moved a bunch of the methods attached to VEvent to ComponentBase so that the Todo and Journal objects would also have access to them, without needing to duplicate the methods
• For a couple of the methods like setPriority and setResources I made them private on the ComponentBase and then added public methods on the Components they're valid in, Event and Todo. I'm not super married to this idea, there is probably a better way to handle this without duplicating too much code.
• I added new things to the bottom of the constant lists, and left all of the ComponentBase (previously Event) methods in the same order.
• The different components are ordered:
  • Struct
  • serialize methods (serialize, Serialize)
  • New method
  • Two Add methods (AddEvent, AddVEvent)
  • Getting all components method (Events)
  • Any property setters only for that component (SetEndAt)
  • Property setters that are shared between some (but not all) components (SetPriority)
  • Any existing getters (GetEndAt)

[spslater]

I've already notice a typo in components.go where the VTodo setGeo method should be SetGeo to make it public. I will hold off on pushing another commit in case any changes need to be made.

[spslater]

Workflow failed seems to be caused by an incident at Github, issue is resolved now, so we should be able to just rerun it.

https://www.githubstatus.com/incidents/0d1bcqt29hm2

[arran4]

Okay attempting to re-run them all

[arran4]

@spslater It still seems to be failing. However for much clearer reasons:

Run go test ./...
go: downloading github.com/stretchr/testify v1.7.0
go: downloading github.com/pmezard/go-difflib v1.0.0
go: downloading gopkg.in/yaml.v3 v3.0.0-20210107192922-49[6](https://github.com/arran4/golang-ical/actions/runs/4600085447/jobs/8187337848?pr=66#step:5:7)545a630[7](https://github.com/arran4/golang-ical/actions/runs/4600085447/jobs/8187337848?pr=66#step:5:8)b
go: downloading github.com/davecgh/go-spew v1.1.1
# github.com/arran4/golang-ical [github.com/arran4/golang-ical.test]
Error: ./components.go:6[9](https://github.com/arran4/golang-ical/actions/runs/4600085447/jobs/8187337848?pr=66#step:5:10)9:4: syntax error: unexpected newline, expecting comma or }
FAIL	github.com/arran4/golang-ical [build failed]
FAIL
Error: Process completed with exit code 2.

[spslater]

Whoops, not sure how I missed that, fixed it and a couple other things I caught.

[arran4]

@spslater There is a conflict.

[arran4]

@spslater I have attempted to resolve the conflict. Please take a look at some stage.

[arran4]

Bah I broke it.

[arran4]

Okay.. Github merge helped me mangle that.

[arran4]

Force pushed removal. Shouldn't have closed it though.

[spslater]

Looks like that force push overwrote some of the changes, I will see if I can get a clean merge with some small changes from my local copy.

[arran4]

Bah trashed more commits than I should have.

I had to restart the merge please look at #84

[arran4]

Looks like that force push overwrote some of the changes, I will see if I can get a clean merge with some small changes from my local copy.

I think I salvaged it. Perhaps compare?