chore: update vagrantfile to forward vm port to access grpc api & fix validations

[jmickey]

What this PR does / why we need it:

This PR achieves 2 things:

1. Updates the Vagrantfile to forward port 9090 from the guest VM to the host. This allows you to connect to the gRPC server from BloomRPC running on the host machine. NOTE: You need to run flintlockd with the --grpc-endpoint=0.0.0.0:9090 flag, otherwise the connection is rejected.
2. Fixes some incorrect validations. GuestMAC is optional, and the file validation is rubbish.

Checklist:

• squashed commits into logical changes

[codecov-commenter]

Codecov Report

Merging #170 (94ab549) into main (12b503c) will increase coverage by 6.90%.
The diff coverage is 56.50%.

@@            Coverage Diff             @@
##             main     #170      +/-   ##
==========================================
+ Coverage   40.09%   47.00%   +6.90%     
==========================================
  Files          32       45      +13     
  Lines        1444     1951     +507     
==========================================
+ Hits          579      917     +338     
- Misses        789      930     +141     
- Partials       76      104      +28     

Impacted Files	Coverage Δ
core/application/app.go	100.00% <ø> (ø)
core/application/errors.go	0.00% <0.00%> (ø)
core/application/query.go	0.00% <ø> (ø)
core/application/reconcile.go	0.00% <0.00%> (ø)
core/models/volumes.go	0.00% <ø> (ø)
core/plans/microvm_update.go	0.00% <0.00%> (ø)
core/steps/runtime/dir_create.go	42.30% <ø> (ø)
core/steps/runtime/initrd_mount.go	0.00% <ø> (ø)
core/steps/runtime/kernel_mount.go	0.00% <ø> (ø)
core/steps/runtime/volume_mount.go	0.00% <ø> (ø)
... and 34 more

---

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[Callisto13]

Fixes some incorrect validations. GuestMAC is optional, and the file validation is rubbish.

aha! these are the things that were yelling at me 🙇‍♀️

[Callisto13]

NOTE: You need to run flintlockd with the --grpc-endpoint=0.0.0.0:9090 flag, otherwise the connection is rejected.

is this bit in the docs?

[jmickey]

is this bit in the docs?

@Callisto13 - wasn't sure the best place to put it to be honest. Maybe the quick-start?