Update base64 dependency

[vihu]

Summary

This updates base64 dependency from the pretty old 0.13 to current 0.21.2 and does the necessary changes to token creation.

Furthermore:

• Fix docker-compose to use soft and hard ulimits
• Update Auth default to fix clippy warnings

Local test run result:

        PASS [   0.044s] arangors::transaction test_start_transaction
        PASS [   0.083s] arangors::document test_get_read_document
        PASS [   0.089s] arangors::connection test_jwt
        PASS [   0.092s] arangors::document test_delete_remove_document
        PASS [   0.114s] arangors::database test_fetch_current_database_info
        PASS [   0.099s] arangors::index test_list_indexes
        PASS [   0.106s] arangors::graph test_graph_retrieval
        PASS [   0.112s] arangors::document test_post_create_document
        PASS [   0.111s] arangors::document test_post_replace_document
        PASS [   0.086s] arangors::index test_ttl_index
        PASS [   0.112s] arangors::document test_patch_update_document
        PASS [   0.113s] arangors::document test_get_read_document_header
        PASS [   0.101s] arangors::index test_hash_index
        PASS [   0.089s] arangors::index test_persistent_index
        PASS [   0.087s] arangors::index test_skiplist_index
        PASS [   0.085s] arangors::transaction test_commit_transaction
        PASS [   0.085s] arangors::transaction test_abort_transaction
        PASS [   0.105s] arangors::index test_geo_index
        PASS [   0.189s] arangors::analyzer test_create_and_drop_norm_analyzer
        PASS [   0.189s] arangors::aql test_aql_bind_vars
        PASS [   0.204s] arangors::collection test_create_and_drop_edge_collection
        PASS [   0.204s] arangors::collection test_put_rename
        PASS [   0.215s] arangors::view test_create_and_drop_view
------------
     Summary [   0.309s] 70 tests run: 68 passed, 2 failed, 0 skipped
        FAIL [   0.084s] arangors::collection test_put_unload
        FAIL [   0.055s] arangors::database test_get_version
error: test run failed

[vihu]

I'm actually not certain about the following two failing tests, but they also seem to be failing on the main branch?

        FAIL [   0.084s] arangors::collection test_put_unload
        FAIL [   0.055s] arangors::database test_get_version

[fMeow]

The failing two might be related to changes in arangors API. I will aceept this merge PR.