[teeracle] configurable datadir

[mosonyi]

It seems all data is generated into the same folder where the binary is.
After dockerization of teeracle it is hard to keep the persistency.

Files needed to be persisted:

aes_key_sealed.bin
ed25519_key_sealed.bin
light_client_db.bin
light_client_db.bin.1
sidechain_db

I suggest introducing a new command line argument --datadir to handle docker mounts more easily.

[clangenb]

Tasks:

• Add base path to io-handler of the shielding key (rsa3072): Allow setting a base path for shielding-key file IO #1318
• Add base path to io-handler of the signing key (ed25519) Introduce signing key repo and allow setting the base path of the signing key file IO #1321
• Add base path to io-handler of the state key (aes) Allow setting path of the State Key (AES) #1324
• Add base path to io-handler of the light-client Allow setting the BasePath by adding StateDir abstraction that helps with fs operations relevant for the state  #1325
• Add base path to the sidechain-db Add basepath to sidechain db #1327
• Last slot is no longer persisted to file last slot is no longer persisted to file but just a static ref #1328
• Add base path to light-client db Add base path to light-client initialization #1330
• Pass base-path as a CLI from the service into the enclave Introduce CLI for a configurable data-dir #1331